TETR.IO

TETR.IO
TETR.IO logo
Developer(s)	osk
Designer(s)	garbo GlitchyPSI (Assisting)
Programmer(s)	Dimentio Dr Ocelot flash (Assisting)
Platform(s)	Web (Native) Desktop: Windows, Linux, macOS
Release	INDEV February 19, 2019 INFDEV January 31, 2020 Alpha March 22, 2020 Beta July 26, 2024
Latest release	Beta 1.6.1 / February 16th, 2025 Desktop V9 / March 9th, 2024
Gameplay info
Next pieces	1~6 (default 5)
Playfield size	10 × 40 (default)
Hold piece	Yes (default)
Hard drop	Yes (default)
Rotation system	SRS+ (default), SRS, SRS-X, ARS, NRS, ASC, Tetra-X, None

TETR.IO is a free-to-play online multiplayer and singleplayer game developed by osk. Players can play against friends and foes all over the world and claim a spot on the leaderboards, found in the Tetra Channel. It is referred to as a free-to-win, modern yet familiar online stacker game in the same genre as Tetris.

Multiplayer

In multiplayer, players can play online multiplayer games against each other. You can choose to play in one large Royale lobby or in a room created using the Custom Rooms option. The host of a room can change settings for the room such as Spin bonuses, player limit, the amount of next pieces shown, and more. Rooms that are set to public by the host will appear in the Room Listing.

Custom rooms with 3 or more players play similarly to Tetris 99 along with alike targeting options, though you cannot manually target a specific player by default. A garbage/gravity margin time system is enabled by default, which causes garbage sent/gravity to increase gradually after a specified amount of time.

Mechanics

TETR.IO includes many modern stacker staples such as Garbage (notably using "change on attack" randomization rules), Gravity, and the quintessential Line clear, but also contains several mechanics unique to it.

Combo System: "Multiplier"

A table detailing the Multiplier combo and B2B Chaining mechanics combined. Yellow cells indicate the attack will cause a "spike", red cells indicate that the attack would cause a top-out if no garbage is cancelled, and purple cells indicate an attack that can cause a "spike KO". Note that the All Clear attack value is outdated.

By default, TETR.IO utilizes a very different combo system to other Tetris games and clones. This system is known as the Multiplier combo system. It nerfs the usually overpowered "four-wide" combo setup heavily, and awards combos that finish with a Quad or T-Spin with a large spike. This system is enabled by default in all multiplayer modes and Zen, and can be toggled in the Custom Room settings.

In the Multiplier system, larger attacks are affected by combo more than smaller ones. The exact value is $base*(1+0.25x)$ where $x$ is combo. If the base attack is 0, the function $ln(1+1.25x)$ is used for 2-combo and above.

Since TETR.IO is played on a grid, the resulting value must be rounded to a whole number. How this is done depends on the "Rounding Mode" setting. Taking a 1-combo Double (1.25) for example:

• DOWN: values are rounded down, meaning it will always send 1.
• RNG: values use weighted randomness, meaning it has a 25% chance to send 2 instead.

Quick Play uses RNG mode. Other multiplayer modes and Zen use DOWN mode by default. Blitz and Sprint use other scoring systems, so this system is not used.

Back-to-Back Charging

Various stages of B2B Charging.

Back-to-Back Charging is a mechanic added in Beta 1.0.0 on July 26th, 2024 alongside the new Quick Play mode. This is the default mechanic used in multiplayer games, replacing Back-to-Back Chaining.

To use this mechanic, one must do several "difficult line clears" (including Quads, T-Spins and All-Spins if enabled), without clearing a Single, Double, or Triple in between each one. This adds one extra line of garbage to each attack until the streak is broken.

When a player gets a Back-to-Back streak of 4, they will begin charging up a Surge attack. This has a starting power of 1 line in Quick Play and 4 lines in other modes. Each difficult line clear adds 1 line to Surge, so a higher B2B streak will result in a larger Surge attack. For example, if a player has an 8 B2B streak, then 8 lines will be charged (5 lines in Quick Play).

When the player breaks their B2B streak, all of the player's stored Surge lines will be sent at once. It splits into three segments, with the first and sometimes second segment keeping the remainder if the total lines are not a multiple of 3.

Back-to-Back Chaining

Back-to-Back Chaining was introduced in Alpha 2.3.2 on 24th of April, 2020 as an experimental feature which quickly became a popular quirk for many, and became a default mechanic the day right after it was introduced. It was replaced with Back-to-Back Charging in Beta 1.0.0, and in Tetra League's pre-season in Beta 1.1.0.

Back-to-Back Chaining rewards the player with more lines per attack as their streak increases:

Range of B2B streak	Displayed B2B count	Extra lines sent per attack
0-1	(none shown)	0
2-3	B2B x1 - B2B x2	1
4-8	B2B x3 - B2B x7	2
9-24	B2B x8 - B2B x23	3
25-67	B2B x24 - B2B x66	4
68-185	B2B x67 - B2B x184	5
186-504	B2B x185 - B2B x503	6
505-1370	B2B x504 - B2B x1369	7
1371-3725	B2B x1370 - B2B ×3724	8

This system effectively increases forever, seeming to progress similarly to a square root function. Values up to level 8 were posted in a pinned message by osk in the official TETR.IO Discord server's #tetrio-general channel.

In a Custom Room, both Back-to-Back mechanics can be toggled separately using their respective game settings by the host. It was replaced with Back-to-Back Charging as the default setting in the Season 2 Pre-Season.

All-Mini

All-Mini was added in Beta 1.0.0 on July 26, 2024. This rule allows all pieces to perform Spins. Spins for pieces other than T use immobile detection and are counted as Mini-Spins. It used to be the default rule until it was replaced by All-Mini+ after Beta 1.5.0.

All-Mini+ was added in Beta 1.5.0 on January 18, 2025, allowing T pieces to use immobile detection as well. It replaced All-Mini as the default for all multiplayer gamemodes and Zen.

Passthrough

This mechanic allowed two players to send garbage to each other without cancelling the garbage sent if one attack is sent before the other is received. Garbage takes 20 frames, or 0.333 seconds, to travel to another player. During this time, it cannot cancel or be cancelled by any incoming garbage and plays a special sound when it does.

As of Alpha 6.1.2, it is disabled by default in all gamemodes. It can be enabled by toggling the "Garbage Passthrough" option under the "Gravity and Margin Time" category. This mechanic historically has gone through many controversies leading to its removal as a default mechanic -- refer to the Professional Concerns section for more info.

Clutch Clear

Clutch Clears were introduced in Alpha 2.5.3. When enabled, if you cleared lines when you would have caused a lock out, you would be able to keep playing. This mechanic became redundant when lock out was disabled by default.

Clutch Clears were reworked in Beta 1.5.0. If you clear lines when you would have caused a block out, your next piece will be pushed above the stack, allowing you to keep playing.

A "CLUTCH" pop-up and sound effect appears when it triggers. Triggering multiple Clutch Clears in a row will display "DOUBLE CLUTCH", "TRIPLE CLUTCH", and so on. This continues up to "DECA" then switches to "CLUTCH xnumber".

Quick Play

Quick Play is the main free-for-all room in TETR.IO, aiming to be a more casual, unranked experience, and was revamped in Beta 1.0.0. The goal of this mode is to climb as high as possible and battle it out in a large free-for-all lobby. Upon being eliminated, players can promptly start a new run without waiting for the game to end. It has two leaderboards that reset weekly: Quick Play and Expert Quick Play (Expert Mode enabled).

Gameplay changes

Quick Play makes some changes to the base gameplay.

B2B Charging Surge starts with an attack of 1 line, instead of 4 lines like in other multiplayer modes. All Clears send only 3 lines but add +2 B2B. 0-combo non-Spin Singles always send 1 line, except in Expert Mode or any reversed mod.

Garbage messiness is modified from change-on-attack. Each individual line has a certain chance to change columns, known as garbage messiness. Between separate attacks, this chance is multiplied by 2.5x. This means that garbage is not specifically tied to the queue.

When receiving garbage, the lines will wait in queue before becoming active. It first appears a transparent yellow, then transparent red, then opaque red once active. Placing a piece before the lines are active will not cause garbage to enter. Garbage becomes active faster per floor and if the Expert Mode mod is enabled.

Floors

Zenith Tower, the stage of Quick Play, is divided into ten floors by altitude. Reaching a new floor for the first time, other than floors 1 and 10, unlocks a new mod.

Floor	Name	Height range(m)
1	Hall of Beginnings	0–50
2	The Hotel	0–150
3	The Casino	150–300
4	The Arena	300–450
5	The Museum	450–650
6	Abandoned Offices	650–850
7	The Laboratory	850–1100
8	The Core	1100–1350
9	Corruption	1350–1650
10	Platform of the Gods	1650 and above

Climbing

The Climb Speed bar at rank 8.

Players climb the Zenith Tower by sending lines and eliminating other players.

Climb Speed is ranked up by sending and cancelling lines, indicated by a progress bar and growing shapes under the board. You start at Climb Speed 1, and there is no upper limit. You climb at +0.25m/s, starting at 0.25m/s, per Climb Speed rank passively.

Sending, but not cancelling lines, will gain bonus altitude, shown as a flashing +NUMBER above your username. Each line sent immediately boosts you by 1 second of your Climb Speed. KOs count as 15 lines, but do not contribute to Climb Speed progress.

Climb Speed decays over time and decays faster at higher ranks. When you gain a rank, this decay will pause for 5 seconds. However, each time you lose and regain the same rank, this shortens by 1 second (down to 1 second). This can be reset back to 5 seconds by reaching 50% to the next rank.

In Expert Mode, Climb Speed decays faster, and cancelling lines does not contribute to Climb Speed progress.

In Duo, both players contribute to the same Climb Speed and altitude, but contribute half as much each.

HYPERSPEED

The HYPERSPEED text.

The HYPERSPEED speedrun overlay with time splits.

When you reach a certain Climb Speed rank specific to each floor before reaching floor 6, you enter HYPERSPEED. You must reach a rank of 8 on floors 1 or 2, rank 9 on floors 3 or 4, or rank 10 on floor 5. You cannot enter HYPERSPEED after floor 6. HYPERSPEED ends when you reach floor 10 or fall below Climb Speed rank 7. As of Beta 1.6.1, entering HYPERSPEED is only possible when no modifiers are enabled. Previously, HYPERSPEED was available with every modifier except Duo or any reversed mod.

In HYPERSPEED, a speedrun overlay shows up with the player's progress, the time the player completed each floor, and their best times. The player will also have a glowing rainbow overlay in the leaderboard. Otherwise, HYPERSPEED is mostly cosmetic and does not directly affect climbing.

Fatigue

To prevent runs from going on forever, the player receives a debuff every minute starting from 8 minutes up to 12 minutes. These debuffs stack and last until the player tops out. The board darkens before each Fatigue debuff to warn the player.

Time	Debuff	Message
8:00	+2 permanent lines	FATIGUE SETS IN...
9:00	Receive 25% more garbage	YOUR BODY GROWS WEAK...
10:00	+3 permanent lines (total 5)	ALL SENSES BLUR TOGETHER...
11:00	Receive 25% more garbage (total +50%)	YOUR CONSCIOUSNESS FADES...
12:00	+5 permanent lines (total 10)	THIS IS THE END.

Additionally, at 3, 5, and 7 minutes, your chance of being targeted increases. No message appears for this effect however.

Attacking

Attacking players in Quick Play is done by sending lines. If an attack causes a player to top out, a KO is attributed to that player's attack. When sending an attack of over 4 lines, it will be split up into separate attacks of up to 4 lines each. Garbage is multiplied the higher up an attack travels, known as "height multiplier".

You cannot change targeting modes or manually target players in Quick Play. Instead, all players have a hidden "Targeting Factor" value that determines how likely they are to be targeted. Targeting Factor increases over time during a run and is affected by some mods. Targeting Factor decreases temporarily when receiving garbage, known as "Targeting Grace". Players also generally target others on the same floor.

Windup

The Windup alert.

Windup is a mechanic that triggers when any individual received attack contains 8 or more garbage lines. When this happens, an alert will appear, and the attack will be split up into portions of 4 lines. It can only be split up to 4 times; the last portion will contain all leftover lines. For example, an attack of 9 would become 4+4+1, and an attack of 21 would become 4+4+4+9.

When a Windup appears, it takes 1 second for the attack to start coming in, and 0.5 seconds between each split portion. Only one Windup can happen at a time; further attacks are queued until the Windup ends.

When using the Volatile Garbage mod, Windup is triggered before garbage is doubled. This means that an attack of 15 would enter normally, and an attack of 16 would trigger Windup.

Mods

Quick Play features a total of 9 mods that can be enabled before starting a run. 8 of them are unlocked by reaching a certain floor, while the Duo mod requires one player to be a TETR.IO Supporter. Each unlockable mod makes gameplay more difficult, though some also have a potential upside. You cannot unlock mods or get the Zenith Explorer achievement in a Duo.

Mod name	Effect	Unlock condition
No Hold	Disables the ability to hold pieces.	Floor 2
Messier Garbage	Garbage is significantly messier.	Floor 3
Gravity	Gravity increases and lock delay decreases per floor.	Floor 4
Volatile Garbage	Receive and cancel double the normal amount of garbage.	Floor 5
Double Hole Garbage	Garbage may sometimes spawn with two holes.	Floor 6
Invisible	Non-garbage blocks become invisible and are shown briefly every 5 seconds.	Floor 7
All-Spin	Spins with non-T pieces are considered full Spins instead of Mini-Spins. Performing the same clear or Spin twice in a row spawns a Wound line. Action text persists after performing an action.	Floor 8
Expert Mode	Lowered garbage delay. All garbage lines enter at once instead of rolling in one by one. 0-combo Singles no longer send any lines. Cancelling garbage does not contribute to climb speed. Chance of being targeted increases. Garbage is messier.	Floor 9
Duo	Allows two players to play as a single team. If one tops out, the other can revive them by completing up to 3 random tasks.	One player must be a Supporter

Wound lines

Wound lines on a player's board.

Wound lines are a type of unclearable garbage that spawn when a player performs the same clear or action twice or more in a row with the All-Spin mod enabled. Wound lines consist of blocks that shift colors and display a number indicating how many clears one must perform before they turn into regular garbage. The number of clears required increases with each floor. Wound lines are unaffected by the Volatile Garbage and Double Hole Garbage mods. All Clears can still be achieved even if Wound lines are present.

Reviving

A Duo partner awaiting revival.

When one player in a Duo tops out, the run isn't over yet. To revive their partner, the surviving player must complete 1-3 revive tasks. This will clear their board and allow them to keep playing. These revive tasks are grouped into tiers ranging from F to A tier:

Tier	Task	Notes
F	Perform a 3-Combo
F	Clear 2 Doubles
F	Clear a Quad
F	Clear 6 Lines
F	Clear a Single using an O-Piece
F	Clear a Double using an O-Piece
F	Clear a Double using an S or Z-Piece
F	Clear a Triple using an L or J-Piece
F	Clear 3 lines while holding an I-Piece	Does not appear with No Hold.
F	Use Hold 8 times	Does not appear with No Hold.
F	Rotate 20 times
F	Clear 2 Singles in a row
E	Perform any Spin	The Spin does not require clearing lines.
E	Clear a T-Spin Single
E	Clear a T-Spin Double
E	Clear an S/Z-Spin
E	Clear an L/J-Spin
E	Perform a 5-Combo
E	Clear 2 Lines using horizontal I-Pieces
E	Place 20 pieces
E	Send 6 Attack	Cancelling is allowed.
E	Place 2 O-Pieces in a row
E	Place 12 pieces while only rotating counterclockwise
E	Clear 6 Singles without starting a combo
D	Clear 4 Doubles
D	Place 3 pieces in a row without moving or rotating	Holding is allowed.
D	Place 14 pieces in a row without clearing any lines
D	Clear 2 Doubles using S or Z-Pieces
D	Clear 2 Triples using L or J-Pieces
D	Clear an I-Spin
D	Clear a Quad in the upper half of the board
D	Rotate 80 times
D	Clear a Quad while on a 2+-Combo
D	Clear 2 Singles in a row using S or Z-Pieces
D	Perform a 3-Combo without using Hold
D	Perform 3 Spins that don't clear any lines
D	Perform 2 S/Z/L/J-Spins
C	Clear a T-Spin Triple
C	Place 25 pieces in a row without using Hold	Does not appear with No Hold.
C	Clear 3 Triples
C	Reach B2B x4
C	Clear a Quad in 2 different columns
C	Use Hold on 12 pieces in a row	Does not appear with No Hold.
C	Place 10 pieces without releasing Soft Drop
C	Have part of your stack in the top 3 rows for 3 seconds
C	Clear 10 Lines without clearing with T or I-pieces
C	Clear an S/Z-Spin Triple
C	Clear 2 Doubles consecutively using two O-Pieces
C	Clear 4 T-Spin Minis
C	Send 14 Attack	Cancelling is allowed.
C	Clear 3 Doubles with the same type of piece	Clearing a Double with another piece resets the task; other Clear types are allowed.
C	Clear Garbage using a L/J-Spin
C	Clear Garbage using a S/Z-Spin
C	Place 3 O-Pieces in column 1
C	Clear 2 Spins in one combo
C	Clear a Single with an I-Piece without moving or rotating
C	Place 6 Pieces without releasing DAS
B	Clear 6 Lines using O-Pieces
B	Clear Spin-Clears with 3 different pieces
B	Clear 4 Quads
B	Place 5 pieces in a row without moving or rotating	Holding is allowed.
B	Clear an L/J-Spin Triple
B	Clear 2 Quads in a row
B	Clear 8 Singles without doing other clears or using Hold
B	Have no Garbage Lines on your board for 4 seconds	Does not appear in reversed Duo.
B	Rotate 300 times
B	Don't cancel any garbage for 8 seconds
B	Clear a T-Spin Double with the Piece pointing up
B	Clear a Double with an O-Piece without moving or rotating
B	Place 3 T-Pieces without rotating any
B	Clear a T-Spin Double while on a 2+-Combo
A	Perform a 7-Combo
A	Clear an I-Spin Double
A	Clear two S/Z-Spin Doubles consecutively
A	Clear two L/J-Spin Doubles consecutively
A	Perform a Color Clear	Performed by clearing all non-garbage minos.
A	Clear 40 Lines
A	Clear 4 Spins in one Combo
A	Clear a T-Spin Double/Triple centered in column 1 or 10	Requires a floating overhang.

Using the formula $difficulty=floor+timesrevived$, the task tiers are chosen using this table:

Difficulty	Tasks
1	F×1
2	F×2
3	F×3
4	F×2 E×1
5	F×1 E×2
6	E×3
7	E×2 D×1
8	E×1 D×2
9	D×3
10	D×2 C×1
11	D×1 C×2
12	C×3
13	C×2 B×1
14	C×1 B×2
15	B×3
16	B×2
≥17	A B A

For 'difficulty' scores under 17, the tiers of each task are ordered randomly. Otherwise, for scores 17 and above, the tiers are always ordered A-B-A as of Beta v1.6.0.

Reversed mods

Reversed mods were added in Beta 1.5.0 on January 18, 2025. Each mod (except for Duo) has a reversed version that is significantly harder, but cannot be combined with other mods. To unlock a reversed mod, you must climb a total of 30,000m with its base version. Enabling multiple mods will gain progress for them at the same time. You cannot gain any progress in a Duo.

Mod name	Base version	Effect	Description
Asceticism	No Hold	Hold piece is disabled. 1 piece preview. No ghost piece. Spins are downgraded to Mini-Spins. Random piece generation. Garbage holes are 2-wide.	A detachment from even that which is moderate.
Loaded Dice	Messier Garbage	Garbage is significantly messier. 1.15 seconds of line clear delay is added. You start with a fixed pattern of 6 circles on your board.	In a rigged game, your mind is the only fair advantage.
Freefall	Gravity	Gravity starts at 20G. Lock delay decreases per floor.	In retrospect, the ground you stood on never existed in the first place.
Last Stand	Volatile Garbage	Playfield is 14 blocks tall. Receive 3x garbage, but garbage is cleaner. The next two garbage hole positions are indicated.	Strength isn't necessary for those with nothing to lose.
Damnation	Double Hole Garbage	Start with 12 rows of checkerboard garbage. Garbage lines have 6-7 holes. Receive half as much garbage. Garbage cannot be cancelled.	No more second chances.
The Exile	Invisible	Pieces become invisible permanently. Only the top 3 rows of garbage are visible. Start with 3 separate lines of garbage.	Never underestimate blind faith.
Warlock	All-Spin	In addition to base effects: Penalties become 20 wound lines. Every non-Spin line clear counts as a Single. Start with 10 separate lines of garbage. Garbage is messier.	Into realms beyond heaven and earth.
The Tyrant	Expert Mode	In addition to base effects: Climb Speed no longer gains altitude over time. KOs grant 8 instead of 15 base altitude. You lose altitude at an increasing speed per floor. Fatigue has stronger and additional debuffs. Chance of being targeted increases. Receive more garbage the longer you spend in one floor.	Fear, oppression, and limitless ambition.

The starting board for Loaded Dice.

The starting board for Damnation.

Example of garbage in Damnation.

The Tyrant uses a different set of Fatigue effects, which are as follows:

Time	Debuff	Message
6:00	Garbage received becomes messier	YOUR POWER SLIPS…
7:00	Receive 25% more garbage	WHISPERS OF DISCONTENT SPREAD…
8:00	+3 permanent lines	PROTESTERS LINE THE STREETS…
9:00	Receive 25% more garbage (total +50%)	YOUR CLOSEST ALLIES DEFECT…
10:00	+5 permanent lines (total 8)	PARANOIA CLOUDS YOUR JUDGEMENT…
11:00	Garbage becomes even messier	THE REVOLUTION HAS BEGUN…
12:00	+12 permanent lines (total 20)	THE END OF AN ERA.

Development

Quick Play went through a number of concepts before coming to its current gameplay.

The first concept closely resembled old Quick Play, being more of an improvement than a new gamemode. Players were split evenly between 5 arenas which acted as separate FFA rooms. After an arena's round ended, players would move to the next or previous room depending on their final ranking. These rounds would last around 2 minutes, cutting down on the old Quick Play's waiting times. However, it wasn't enough of an improvement for an entirely new system.

The second concept was a continuous free-for-all where players could freely drop in or out. The tower was split into 8 floors where getting a KO moved you up and topping out moved you down. This was also where the Fatigue mechanic originated, preventing players from staying on the same floor too long. The issue was that building a system off KOs was too random, and a player's ability to survive increased exponentially with their skill, making it hard to balance around.

Royale

Royale, formerly known as Quick Play, is another free-for-all room in TETR.IO, which, since Alpha 6.4.0, uses the ROYALE game mode with a dynamic garbage queue depending on the number of remaining players. Prior to this version, the standard versus format was used, with fixed, less forgiving garbage mechanics.

Tetra League

An illustration of the Season 1 Tetra League mechanics. Currently outdated as of August 2024.

Tetra League is the ranked mode in TETR.IO. Each game of Tetra League is a 1v1 match where both players play matches until a certain number of wins. This number is 3 for ranks A+ and below, 5 for ranks SS and below, and 7 for ranks U and above, based off the higher of the two player's ranks.

The player has a TR (Tetra Rating) value, which is based on Glicko-2. TR increases for each match won and decreases for each match lost- individual rounds do not count. When playing this mode for the first time, the player must play at least 10 matches, referred to as "rating games", to display their TR.

A letter rank is assigned to all players with less than 100 RD (Rating Deviation) based on their percentile on the leaderboards. RD decreases to a lower limit of 58 RD when playing Tetra League regularly, and increases at a flat rate of 1 RD per day after one week of inactivity up to a maximum of 350 RD.

As of its public release, players must be registered and be at least level 10 to enter. Anonymous players cannot play this mode. When the mode was first released, only INFDEV testers and supporters were eligible for the mode.

Solo

The game also includes solo modes, two of which have leaderboards: 40 Lines and Blitz.

For all modes except Zen, Stride Mode can be activated. This option speeds up the countdown by changing it from "3-2-1-GO!" to "READY-SET-GO!", allows the retry key to be tapped instead of held, reduces the time to exit the solo game by holding the forfeit key, speeds up all animations at the start and end of games, and prevents the first piece from being either S, Z, or O except in Custom Games.

All solo modes have a scoring table similar to the ones in guideline games, shown here:

Line Clear/Action	Points Scored
Single	100
Double	300
Triple	500
Quad	800
Spin Zero	400
Spin Single	800
Spin Double	1200
Spin Triple	1600
Spin Quad	2600
Mini Spin Zero	100
Mini Spin Single	200
Mini Spin Double	400
Mini Spin Triple	800
Mini Spin Quad	1600
All Clear	3500
Back to Back "difficult" line clears	$x*1.5$ (where $x$ is the point value of the line clear)
Combos	$x*50$ (where $x$ correlates to the current combo value)

All point values are multiplied by your current level, except for Zen mode.

In addition to this table, simply dropping a piece will award a flat number of points not affected by level:

Action Taken	Points Scored
Hard Drop	2 per cell dropped
Soft Drop	1 per cell dropped

40 Lines

In 40 Lines, the objective is simply to clear 40 lines as fast as possible. Due to the lack of ARE and a 0 ARR handling option, the only limit to your speed is how fast you can stack.

Pro mode can be enabled, which displays an input counter on the left, a finesse counter on the right, and number of lines left at the top of the board.

Blitz

Blitz is similar to Ultra, requiring the player to score as many points as possible within two minutes. Unlike Ultra, a level system similar to Marathon with an increasing line goal for each level is added:

Level	Lines required to level up	Total lines cleared	Gravity (seconds per row)	Gravity (G)
1	3	3	1.0	0.0167
2	5	8	0.643	0.0259
3	7	15	0.404	0.0412
4	9	24	0.249	0.0670
5	11	35	0.150	0.111
6	13	48	0.0880	0.189
7	15	63	0.0505	0.330
8	17	80	0.0283	0.588
9	19	99	0.0155	1.08
10	21	120	0.00827	2.01
11	24	144	0.00431	3.87
12	26	170	0.00219	7.62
13	28	198	0.00108	15.4
14	30	228	0.00052	20
15	32	260	0.00024	20

Higher levels are possible, but omitted for brevity. This leveling system can be replicated in custom solo games with the "Leveling Speed" option set to 0.42 and "Base Gravity" set to 0.65.

Unlike most other modes, Blitz still does not award All-Spins and therefore only regular three corner detection T-Spins count for extra scoring.

Pro Mode can be enabled, which displays a finesse counter on the left, and the time left at the top of board.

Zen

Zen is an endless mode with no game overs and a special level system, inspired by the mode of the same name from the Bejeweled series, starting with Bejeweled 2, where it was named Endless. You can change various settings from a menu by hovering over the right side of the window. Zen can be played while waiting for the next match in Custom Rooms or in the Tetra League queue.

You gain a static 100 XP per minute while in Zen mode. This caps at 3000 XP per session if you are idle for the majority of the time, meaning that you will need to exit and re-enter Zen after 30 minutes to continue earning XP.

Custom

Players can create their own solo mode and adjust settings such as objective, gravity and garbage. By default, the options match that of a fixed-goal Marathon mode from other Tetris games.

Achievements

Stacker achievement at diamond tier.

In Beta 1.0.0, achievements were introduced. Achievements can be viewed in TETRA CHANNEL in-game, as well as user pages. Players may also choose to feature up to 3 of their achievements on their profile.

There are 5 tiers for each achievement- bronze, silver, gold, platinum, and diamond. Some achievements do not have a bronze or silver tier due to being especially difficult. Tiers can either be determined by percentile or a set threshold.

Achievements contribute to the player's total AR (Achievement Rating), contributing more with each tier. Total AR has its own leaderboard on Tetra Channel. Achievements marked as Unranked will not contribute to the player's AR. Most of these are marked as such due to requiring TETR.IO Supporter or being part of a limited time event.

All achievements except for Secret Grade have their own leaderboards. Viewing an achievement in TETRA CHANNEL displays your leaderboard position and percentage. Achievements marked as "competitive" grant extra AR to players in the top 100 leaderboard, depending on placement. In rare cases, it is possible to gain this extra AR without actually having the achievement.

An achievement may be marked as "hidden", meaning it will only appear to players once they trigger a certain related goal. All Quick Play mod-related achievements are hidden until their required mods have been unlocked.

Badges

Main article: TETR.IO/Badges

Badges are given to registered TETR.IO users to immortalize special accomplishments on their profile. Badges are typically rewarded for placing highly in organized tournaments and events, for especially difficult and rare feats in game, or as rewards in exceptional circumstances.

Some badges, such as Secret Grade, 20TSD, and 10PC have been superceded by achievements as of Beta 1.0.0, and as such are no longer obtainable.

Rotation System

180 Kicks

A diagram of TETR.IO's 180 kicks, as posted, and pinned, by osk on the official TETR.IO discord server in the "#tetrio" channel.

From 0.6.0-pre0, TETR.IO made its first modification to the guideline kick table, adding a custom 180 kick table. This table is relatively resilient to abusable spins, however there is plenty of room for handy L and J tucks with this system.

In a situation shown to the left, limited to guideline clockwise and counterclockwise spins, the only "clean" downstack would be building up a wall on the left side of the field and spinning a Z in.

Like so:

However, if you have a 180 key bound and a L tetromino in the playfield, simply soft drop,

and 180!

SRS-X

TETR.IO also includes a separate kick table known as "SRS-X" that can only be enabled by the host of a multiplayer room or in a solo Custom game as it is not the default kick table. SRS-X is known for its "more powerful 180 spins" such as the ones seen in NullpoMino or the Heboris Unofficial Expansion. All other kicks are the same as in SRS.

SRS+

A very simple graphic detailing TETR.IO's SRS+'s symmetric attributes, as posted, and pinned, by osk on the official TETR.IO discord server in the "#tetrio" channel.

As of Alpha 5.0.0, TETR.IO uses a modified version of SRS as the default option, in which the I wall kicks are symmetrical along the y-axis, similarly to TGM3; however, the left-side kick tables are mirrored instead of the right side. This allows certain situations that are impossible in regular SRS to be made effectively.

As in Guideline SRS, the shown placement can be achieved by rotating clockwise.

In the symmetric position, this can now be achieved by rotating clockwise or counter-clockwise.

Tetra Channel

The in-game Tetra Channel contains leaderboards with replays for 40 Lines and Blitz, weekly leaderboards with temporary replays for Quick Play and Expert Quick Play, and your last submitted solo, Tetra League or Quick Play replays in the "ME" section. The Players screen lists the top players sorted by their league rating, achievement rating or by the total amount of experience points (XP) accumulated throughout the game. Leaderboards are also capped at the hundredth player.

In addition to the features above, it also shows players who are currently streaming with the TETR.IO category on Twitch. The Tetra News section displays achievements done by players, such as reaching the top ten in either solo mode with a leaderboard, or winning one of TETR.IO's many partnered tourneys. There is also a simple "search bar" at the top of the Tetra Channel, where you can input specific replay IDs or URLs to access them, as well as access specific player cards with a username or User ID.

Standalone Site

In the 5.0.0 update, a standalone Tetra Channel site was released. This site holds most of the same things the in-game Tetra Channel does, with the added benefit of more detailed userpages, extended leaderboards, free access to anyone without an anonymous or registered account, and more detailed server statistics. Specifically, solo leaderboards are extended from the top 100 scores to every user's personal best, the Tetra League leaderboards are extended to every ranked player, and the XP leaderboards are extended to every player above level 100. Furthermore, all "player leaderboards" can filtered by specific countries.

A similar "search bar" to the one found in the in-game Tetra Channel is present in all pages on the site. This search bar takes the user to the requested user page when an exact username and User IDs is entered. A user page is far more detailed than its in-game player card counterpart, and includes extensive information about the user's 40 Lines, Blitz and Quick Play records, links to their top replays in all solo modes, their most recently submitted replays in the last 7 days (30 if they are a Supporter), Tetra League statistics and all match records, and finally a simple Zen mode counter for the user's score and level.

An extended "Tetra News" section is included with this site as well. At the very bottom lies a button labeled "VIEW ALL", which takes you to a dedicated Tetra News section of the site. Here, a news ticket is created whenever any registered user gets a new personal best, reaches a new top rank for that season or achieves one of TETR.IO's badges. This page only displays the last 100 news events, and updates on its own whenever a news event occurs. These news events are known as "Local News" and will display on the newsholder's user page even after it expires from the global news.

Supporter

Supporter is a paid subscription for TETR.IO, being a way to support development as the name suggests. It provides a number of benefits, including being able to play with the Duo mod in Quick Play, further customisation, exclusive chat emotes, increased friends limit, and disabled ads. It can be bought in bulk for a discount or gifted to any number of other players.

Since Alpha 6.0.1, players can gain TETR.IO Supporter tiers by hitting lifetime contribution goals. Starting with Tier 1, Tier 2 (★) is achieved after contributions reach €20, Tier 3 (★★) after €80 and Tier 4 (★★★) after €250. These tiers are purely cosmetic, causing the player's name to appear in a brighter shade of orange in chat and adding a star to their profile.

This image shows the various role colors in TETR.IO.

Reception

Promotional material created by osk for display on the @tetriogame Twitter account, to celebrate the latest New Year's Day.

You can always fetch a list of various real-time stats from the Tetra Channel's main page, including, but not limited to: the exact amount of registered players split up into three categories, global time spent playing TETR.IO across all games, how many of those games have been played and completed, and miscellaneous stats such as pieces placed and how many keypresses total.

On the 3rd of November, 2020, TETR.IO reached the milestone of half a million players. This milestone was celebrated with a "triple XP week" which, as the name sort of implies, tripled the XP players gained for the time the celebration ran.

TETR.IO hit a total of one million players on the 9th of February, 2021. This milestone was celebrated by, once again, temporarily multiplying the XP amounts players gained for the week of the celebration. This time, XP would be quintupled for the first day, then tripled for the rest of the week.

Later on, TETR.IO would reach a total of two million users on the 31st of May, 2021. As well as the same XP multiplication as last time, 500% for one day, then 300% for the rest of the week, users would also be treated to a 25% off discount on TETR.IO Supporter for the entire week. This discount stacked with the regular discounts for buying gifts, or buying in bulk.

Continuing the streak, TETR.IO would celebrate the 3 million player mark on the 17th of September, 2021. This time around, the XP multiplication hit 300%, and TETR.IO Supporter was 30% off instead of 25%. These discounts and boosts would expire just 3 days later, this time around.

And, more recently, TETR.IO's playerbase would make the mark of 4 million players on the 8th of December, 2021. Staying true to form from the previous milestone, players were treated to 400% XP generation, as well as a 25% TETR.IO Supporter discount for only one day.

Professional Concerns: The Removal of Passthrough

Results of the completed passthrough.osk.sh survey, as posted on the TETR.IO Discord server

Many players in the community hold a very low opinion on TETR.IO's Passthrough and, to a lesser degree, Multiplier mechanics. Previously, these mechanics would complement each other in creating unfair situations for both players; so much so that a large community-led discussion regarding the removal of Passthrough was held due to its prevalence in deciding ranked games. Concepts regarding Passthrough removal were always tossed about with nearly any server related to TETR.IO. However, the discussion which led to the official removal of Passthrough began in an official capacity on the 28th of September, 2021, in a Discord thread in the official TETR.IO server. Players were informed of and instructed to leave feedback for a new, experimental toggle for passthrough through the #news channel and in-game patch notes alongside the 6.1.0 update. Thanks to this official push for opinions, the "Passthrough Removal" thread quickly became the second most active in TETR.IO's thread list, leading only behind the Official Character System Thread.

“Please only vote if you've actually played w/ passthrough disabled. I won't be looking so much at the raw vote counts, but rather at the reasons given. Please be sure to fill them out. Thank you for voting!”

—osk "#news". TETR.IO Discord server. October 17, 2021. Retrieved .

While discussion in the thread progressed semi-smoothly, it was necessary to attain an overview of players for and against the change. To solve this issue, osk would set up a site known as https://passthrough.osk.sh/. During the submission period, members were asked to fill out 3 fields.

1. Are you for or against the removal of passthrough?
2. What is your TR? (if any)
3. "Please explain in detail why you have voted to keep/remove passthrough. This is the most important field!"

These questions would be answered by the community, amounting to a total of 649 entries after duplicate or spam entries were filtered out. Of those entries, 243 users voted to keep Passthrough, and 406 users voted to remove it.

“After reading all 649 responses, I've decided to remove passthrough from TETRA LEAGUE and QUICK PLAY, and disable it by default in all custom games.
The main reasoning here being that passthrough generally makes defending harder in an already high-damage game, and most importantly, is far too unpredictable (even pure RNG would be more predictable).”

—osk "#news". TETR.IO Discord server. October 17, 2021. Retrieved .

Although Passthrough was removed, it was still possible to some extent after the update due to networking delays. 6.3.3 completely rectified this phenomenon, dubbed "lagthrough" by the community, with a feature known as Zero Passthrough.

Seasonal events

Main article: TETR.IO/Seasonal Events

TETR.IO holds events for various festivities, usually changing gameplay or visuals.

Staff

TETR.IO staff members are users responsible for moderation and general upkeep of the game and its community. Their main responsibilities include reviewing reports, answering support tickets, and moderating the Discord server.

Staff members have access to the admin panel, which is the main interface for moderation actions. They also (in most cases) have access to the support ticket system, a role in the TETR.IO Discord server which grants them moderation permissions, and access to staff-only Discord channels.

Staff Roles

This image shows the various role colors in TETR.IO.

TETR.IO has four distinct staff roles with varying levels of access and responsibility. Staff roles automatically have access to most Supporter and Verified perks, access to a number of exclusive emotes, and the ability to take host of any in-game lobby.

Community Moderator

The community moderator role was introduced in May 2023. As the entry level staff role on TETR.IO, community moderators handle chat moderation and less involved administrative tasks. Community moderators have a blue name in chat.

Global Moderator

Global moderators are established TETR.IO staff members with extended responsibilities. Global moderators have the authority to handle all types of rule violations, and have a light pink name in chat.

Administrator

The administrator role is functionally similar to the moderator role, with extended permissions to perform certain bureaucratic tasks. Administrators have a hot pink name in chat.

Sysop

Users with the sysop role have full administrative control over TETR.IO. Notably, sysops are the only users with the power to promote new staff members or deploy code changes. This role is exclusively reserved for TETR.IO founder osk, who has a green name in chat.

Staff Members

Staff Member	Role	Title	Appointment
osk	Sysop	osk / TETR.IO Founder (Lead Producer)	Launch - Present
Dimentio	Administrator	TETR.IO Programmer & Administrator	August 2021 - Present
Dr Ocelot	Administrator	TETR.IO Audio & Music Designer, Programmer & Administrator	June 2022 - Present
Garbo	Administrator	TETR.IO Game Designer	November 2020 - Present
Matthew	Administrator	TETR.IO Administrator	Launch - Present
ZaptorZap	Administrator	TETR.IO Administrator	May 2021 - Present
Zudo	Administrator	TETR.IO Administrator	August 2021 - Present
flash	Global Moderator	TETR.IO Assisting Programmer & Global Moderator	Launch - Present
alcazar	Global Moderator	TETR.IO Global Moderator	Launch - Present
deep4amthoughts	Global Moderator	TETR.IO Global Moderator	May 2021 - Present
flowerpetal	Global Moderator	TETR.IO Global Moderator	May 2023 - Present
gebruikersnaam	Global Moderator	TETR.IO Global Moderator	Launch - Present
thugginator	Global Moderator	TETR.IO Global Moderator	Launch - Present
sketchedpurple	Global Moderator	TETR.IO Global Moderator	May 2023 - Present
Blink	Community Moderator	TETR.IO Community Moderator	May 2023 - Present
nook	Global Moderator (former)	TETR.IO Alumni	Launch - June 2022

Development

TETR.IO began its life in the INDEV stage on the 19th of February, 2019. This phase would have extremely closed testing, limited to only osk and his personal friends. Less than a year later, TETR.IO would enter the INFDEV stage on January 31, 2020, when access to the game was opened for testers on a per request basis. During the Infdev release, players were required to represent their IP address to osk via Discord DMs or E-Mails in order to test this version. A month and a half later, the game entered the public Alpha stage on March 22, 2020. This time, all players are free to create/log in to their accounts and play the game.

On May 22, 2020, a desktop client of TETR.IO was released. Aside from being able to open the game without a web browser, this version also touts increased performance, alongside Discord "Rich Presence" integration and more granular control over VSync.

Trivia

A quick graphic detailing all of the level tags available in TETR.IO.

• A player's "level badge" evolves into different shapes and colors every ten levels, starting from level 1.
  • The tetris bot ZZZTOJ hit the level 5000 on October 6, 2023, though there are no visible stats to verify the gold badge.
  • Player STQRM reached level 5000 on October 31, 2024, becoming the first non-bot user to reach level 5000.
• If the "First To" value is higher than 2 in any given multiplayer Battle Royale with less than eight players, the scoreboard at the top of the screen will match the colors of the seven Tetrominos, displaying each player and their current amount of wins.
• If the user uses the command "/kagari" in room chat, they will be greeted with a system message, only the user invoking the command can see, which contains "CMD: :kagari:". The same goes for the command "/maho", but with the system message saying "CMD: :maho:" instead.
• The "WASD" control scheme, one of three choices in the controls config, is a direct mirror of osk's personal controls; the same controls he thought up on the spot in Tetris Friends since he didn't quite like the default controls.
• Some aspects of TETR.IO's UI design are loosely based off the Bejeweled series. An example of this inspiration involves the Zen mode level up animation, which takes inspiration comes from Bejeweled 2 and Bejeweled 3's similarly named Zen mode. You can even draw comparisons down to the color schemes of the Solo mode selection screen to Bejeweled Twist; a game that also has a red "Blitz", turquoise "Zen", and yellow "Challenge" and "Classic" buttons.

An example of concurrent attacks.

• The damage number pop-ups that appear when sending or blocking lines resemble the ones from the video game Persona 5, developed by Atlus' P-Studio. Similarly, when chaining multiple line attacks in a row within a short time between attacks, the damage number will increase and become bigger in size. The stronger the line attacks, the bigger the damage number becomes.
  • Previously, the damage numbers were yellow when sending lines, and only displayed each attack's lines sent separately. A yellow spike counter on the left side of the board would also appear when sending 10 or more lines in a short time. As of Alpha 6.1.0, as part of the preparations for the upcoming Character System, the spike counter was removed in favor of the new damage number that fulfills a similar role.
• It is theoretically possible to clear more than four lines with one piece. This can be done by creating a custom board layout with rows already filled, as line clears are only processed after a piece is dropped. At first, this would simply softlock the game as it tried to find undefined action text. However, starting with Alpha 4.1.0 released on 16th of July, 2020, that issue was removed by adding in the following action text for when players clear more than four lines:

Lines cleared	Action text
5	PENTA
6	HEXA
7	HEPTA
8	OCTA
9	ENNEA
10	DECA
11	HENDECA
12	DODECA
13	TRIADECA
14	TESSARADECA
15	PENTEDECA
16	HEXADECA
17	HEPTADECA
18	OCTADECA
19	ENNEADECA
20	EICOSA
21+	KAGARIS

• Despite these normally impossible actions being recognized through action text, these line clears do not send any lines or count for any score. (If you end up testing this yourself, ensure there are no all clear bonuses in play.)
  • In April Fools' 2024, Bombs-style garbage was introduced, allowing you to clear more than four lines in intended gameplay. Bombs-style garbage has since been added as a permanent setting in Custom Rooms.
• An easter egg exists in the social panel. If you use the search bar to attempt to find someone not in your friends list, you get the message "Couldn't find anyone like that." in place of search results. If you then search for "anyone like that", you will get a different message. This loop continues for quite a bit:

Search query	Ingame response
anyone like that	Couldn't find anyone with that name.
anyone with that name	Couldn't find that person.
that person	Couldn't find the specified user.
the specified user	Couldn't find anyone in your friends list with that name.
anyone in your friends list with that name	Couldn't find who you are looking for.
who you are looking for	Couldn't find any user in your friends list who matches the specified search term.
any user in your friends list who matches the specified search term	...

• • At this point, the error icon will switch from an innocent depiction of Kagari to a more judgemental one.

A quick chart showing the various numerals used in Zen mode.

• Zen levels are accompanied by small symbols in most places. These symbols resolve into custom, expanded roman numerals.
  • When the highest symbol is reached, the sixth 500,000 and onward simply repeats the symbol, breaking the standard. This is unlikely to occur anytime soon, however, as the user BLB attributed with the most Zen levels has yet to break even 20,000.
• Upon loading the game, TETR.IO runs a fully custom benchmark based on the type of rendering WebGL expects from your computer. The results of this test, known as the Feecof test, are then used to preselect a graphics preset according to the following chart:

Feecof score	Graphics preset
Under 300,000	LOW
Above 300,000 and below 600,000	MEDIUM
Above 600,000	HIGH
ABOVE 1,000,000 and with TETR.IO Desktop	ULTRA

• Since TETR.IO's conception, there have been several competitions for increasingly long activities. Here's where those records stand as of the 9th of June, 2022:
  • The longest TETR.IO 40 LINES run currently stands at 2 hours and 40 minutes. It was run by user agar02.
    • Notably, TETR.IO refuses to parse ranked SOLO replays that take over 30 minutes to complete, so this run wasn't officially uploaded to servers, and YouTube/replay files account for the evidence. That said—there's little to no motivating factor to present fake runs of this sort.
  • The longest single persistent play-session was livestreamed over the course of 18 hours by Excadrill on Twitch. This play-session covered over 547 separate "free-for-all" matches, to preserve the drop-in/drop-out "playing with viewers" nature of his usual stream format. Regardless, during this period, no major breaks or periods of inactivity took place, and Excadrill won 114 matches in total.
  • Ever since this statistic has been tracked, the longest explicitly recorded server uptime stands at just over 56½ days, covering the time gap between versions Alpha 6.2.1 and Alpha 6.3.0, although osk believes the real record stands above 2 months.
• Before the release of the Quick Play rework, a teaser video previously titled "Hall of Beginnings - TETR.IO" was posted. In the background was an encoded message that read "Q P 2.0". The first user to decode this message was UNZENTA.
• Each of the Quick Play mods is themed upon a card from the Major Arcana. Many flavor texts allude to their meanings, such as The Emperor being associated with power and authority.
  • Reversed mods are similarly based on tarot reversals, which convey an opposite or darker meaning.
• Quick Play features a dynamic music system.
  • Each floor has its own soundtrack and sting for ending a run on that floor.
  • Depending on how fast you climb, the soundtrack may skip bars to keep up.
  • The lobby theme, Watchful Eye, has instruments fade in and out at random. Drums play while you are spectating a player.
  • When using the Expert Mode mod, the lobby and floor 1 themes will have an electric guitar stem added.
  • When using any reversed mod, all themes become their reprise version. These also have their own names in the soundtrack.
• HYPERSPEED was originally implemented due to concerns that the dynamic music would break if you climbed too fast. It eventually became somewhat of a mechanic with its own visuals and soundtrack.
• If you attempt to send a Quick Play run under 10.0m to chat, you will get the message YOU SHOULDN'T DO YOURSELF THAT SORT OF INJUSTICE. This is to prevent players from flooding the chat with low-effort runs.
• Viewing osk's profile shows that he is based on "The Moon" and has been "Here since the beginning".
  • Since The Moon is not an accessible country to most humans, osk is No. 1 in all of The Moon's country leaderboards.
  • There is a user KAGARI, a character from the anime Rewrite, that similarly lives on The Moon. She is labelled as TETR.IO Co-founder but has zero playtime or activity, other than being gifted Supporter.
• Many achievements contain references in their name or description.
  • "Wabi-sabi" is named after a Japanese aesthetic concept.
  • "Snake Eyes" is a term for rolling two ones with a pair of dice.
    • This achievement was previously named "All the Single Lines" which is a reference to a song by Beyoncé.
  • "Mr. Boardwide" is based on "Mr. Worldwide", which is a nickname for the rapper Pitbull that became an internet meme.
  • "Opener Main", "Speed Player" and "Plonk" are all named after community terms for playstyles.
  • "The Grandmaster" is a reference to the Tetris The Grand Master series, which features similar Gravity and invisible modes.
  • The icon of "Rolling the Snowman" resembles the Greek mythology figure Sisyphus rolling the boulder up the mountain.

External links

• Official website
• Official Discord server
• Official X (Twitter) account
• Desktop client download page
• Issue tracker
• Release log