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Lockjaw was a highly customizable open-source fan game. The overall idea of its customizability was inspired by one of Henk Rogers' interviews. Lockjaw's customizability allows it to simulate other tetromino games such as Tetris The GrandMaster Series and Tetris DS.

This game has been removed on 21st June 2012 following a court ruling. This ruling was that TTC owns some of those "concept" copyrights; the idea of tetriminoes, as well as falling blocks, is copyrighted to TTC. Lockjaw is now extremely outdated and based on a long series of game breaking assumptions and changes (glitchy SRS, pieces move down after rotating from ground, etc.) that Lockjaw must never be played anymore. Instead use another games such as NullpoMino (might soon be deprecated as well), Tetris Best, Tetris Return, or the recent game, tetrisimplementation.


  • Lockjaw Simulation Settings - Players have created lists of option values that simulate well-known games.
  • List of Lockjaw Skins - Players have created various skins and utilities for Lockjaw.


Although Lockjaw is developed to appease Tetris fans, it also satirizes the current state of Tetris. The original set of planned modes, meant to poke fun at Tetris DS,[1] included:

  • Dual Marathon - The keys control both a platform game (in the top window) and standard singleplayer tetris (in the bottom screen). If you die on either window, you lose. Not implemented at all.
  • Ridin' Spinners - This mode exhibits standard singleplayer tetris gameplay. However, if you abuse lock delay or if you perform a T-Spin Triple twist, the music changes to "Ridin' Spinners" by Three 6 Mafia for a few seconds, and the screen spins (as in Lockjaw: The Overdose). Not implemented at all.
  • Low Rider - This mode exhibits standard tetris gameplay, except the visible playfield is 8 (!) rows tall (instead of 20). Implemented, as "Well height" option.
  • Vs. - This mode exhibits standard singleplayer tetris gameplay. However, when you receive an I tetromino (after the first), you also receive four lines of garbage. Implemented, as "Garbage" option.
  • Items - 3/4 of the time you start the mode, it will play annoying music for 2 minutes, give an 86420 error, and quit. The rest of the time, it will play annoying music between 15 seconds and 2 minutes and then behave like standard single player tetris. However, you will recieve random starting orientations, no rotation, and hidden next pieces. The speed starts at 1G. Every time you are given an I piece, you will either receive four lines of garbage or be the target of a banana item. Implemented partially.
  • Beyond Level 20 - The music starts slow, 60 beats per minute. On every beat, the tetromino hard drops. Every time you clear 30 lines, the music speeds up by 10 BPM. Think of it as Shirase mode, DDR style. Implemented, as "Rhythm" speed curve.


Since version 0.01, Lockjaw has been factory-set to its own speed curve, called "Exponential". Versions 0.01 through 0.44 behaves as follows, if n pieces have come out:

Number of pieces Gravity Lock delay
0 ≤ n < 609 1/60G * (259/256)^n 40 frames
n ≥ 609 20G 40/(1 + 3/256 * (n - 609)) frames

Version 0.45 changed Exponential to remove the repeated multiplication by 259/256. Instead, it approximates the curve as a stepwise function over 30-piece sections, doubling gravity precisely every 60 pieces.

In addition, Lockjaw can emulate a few other games' speed curves, controlling ARE, gravity, DAS delay, lock delay, and line clear delay.


Since version 0.01, Lockjaw has been factory-set to its own scoring system. It involves computing the garbage like Tetris DS standard vs. does, then awarding 100 points for each line clear and 200 for each row of garbage.

  • Single: 100 (1L)
  • Double: 400 (2L + 1G)
  • Triple: 700 (3L + 2G)
  • Home run: 1200 (4L + 4G)
  • T-spin: 500 (1L + 2G) per line
  • Back-to-back home run or T-spin: 200 (1G) more

(A "home run" is four lines cleared with one piece, called a "tetris" in products of The Tetris Company. A line clear is "back-to-back" if the line clear before it was a home-run or a T-spin.)

In addition, Lockjaw can emulate a few other games' scoring formulas.

See also

Damian Yerrick's tetromino games
Carbon Engine: freepuzzlearena (1999–2000) | Lockjaw: The Overdose (2000–2006)
Lockjaw Engine: Lockjaw (2006–2008+)

External links