Mechanic First

• Two more, described

  Not Innovation-ranked

  from the official write-ups

  The Innovation lists above are rankings, not reviews — I'm passing on the field's own verdict rather than describing games I haven't played. Two entries elsewhere in the results do come with a published description of the mechanic, and both are worth the click: Tiny Yurts, called a "perfect version of mini motorways" with curvy line merging, and FEAST NIGHT, where you interact entirely through nods and shakes.

  2025 rankings · 2024 rankings · 2023 rankings

• PuzzleScript

  MIT

  HTML5 · 5×5 sprites · negligible

  Write, play, and share entirely in the browser. Because a game is just its ruleset, the whole engine is a machine for testing "what if this one verb worked differently" — which is exactly the question a unique mechanic is the answer to.

  github.com/increpare/PuzzleScript · awesome-puzzlescript

• PuzzleScript Plus

  Fork

  adds mouse, solver, level select, custom sprite sizes

  Auroriax's fork gathers the useful community modifications into one editor. The built-in solver is the interesting part if you're designing rather than playing: it will tell you whether a level you just invented is actually solvable.

  Sibling fork DungleScript renders the same rules as 3D voxels.

I pulled the rulesets for all 114 games in the PuzzleScript gallery from their gists and read the RULES section of each. Below are the twelve whose rules buy the most play, ranked by how much they change about Sokoban per rule spent — rule count shown, and the rule that does the work quoted where it is short enough to read.

1. 
   Sokoban[Sokoban[Sokoban]]increpare · 3 rules
   [ > Player | stationary Crate | no obstacle ] [stationary player2] -> [ | Player | Crate ] [> player2]

   Not spatial recursion — nested move functions. Succeeding at a push on the first board is what supplies the input to the second board, and a push there supplies the third. You are not playing three Sokobans; you are playing one whose controller is another one. Three rules, and the second and third are the same rule shifted down a level.

2. 
   Collapsable SokobanFranklin P. Dyer · 2 rules
   [Wall|...|Player] -> [> Wall|...|Player]

   Standard Sokoban, plus that. Every wall in line with you advances one square toward you, every turn. The room closes as you solve it, so position stops being free and every move spends space you cannot get back. The best ratio in the gallery: one added line, a completely different game.

3. 
   ModalitySean Barrett · 4 rules
   [ > Player Black | Crate Black ] -> [ > Player Black | > Crate Black ]
[ > Player White | Black ] -> CANCEL

   You have a colour. You can push only crates of your own colour, and you cannot step onto the opposite colour at all. Two constraints written as two cancellations, and the board splits into a pair of interleaved mazes you have to solve alternately.

4. 
   Heroes of SokobanJonah Ostroff · 22 rules
   [ > Fighter | Moveable ] -> [ > Fighter | > Moveable ]
[ < Thief | Moveable ] -> [ < Thief | < Moveable ]
[ > Wizard ] -> [ Wizard > Temp ]

   Three verbs on one grid, and you switch between them. The Fighter pushes, and shoves whole chains. The Thief pulls — moving away drags the block after her. The Wizard swaps places with whatever it faces. The most rules on this list and it earns them: the only entry whose difficulty comes from verbs interacting rather than from one twist, and the only one that spawned two sequels.

5. 
   Watch Your StepAaron Steed · 11 rules
   [ > Crate0 | Crate0 ] -> [ | Crate1 ]
late [Floor4 no Object] -> [no Floor Crate0]

   Two ideas stacked, which makes it the densest thing here. Crates merge on collision the way 2048 tiles do — 0 into 0 makes 1, up to 4, and reaching a 4 wins. Meanwhile the floor ages under your feet, and floor that has aged four steps sprouts a fresh crate. The board you cross is the board that refills behind you.

6. 
   Love and Pieceslexaloffle · 2 rules
   late [ Player | GrayBlock ] -> [ Player | Player ]

   Anything grey you touch becomes you, and the win condition is that no grey is left. So the puzzle is spreading, every copy takes your input at once, and succeeding makes you progressively harder to steer. Written by Joseph White, who went on to build PICO-8.

7. 
   the art of cloningRosden Shadow · 6 rules
   [ > Player | Crate ] -> [ player | > Crate ]

   Look closely at the right-hand side: the > in front of Player is gone. You push the crate and you stay exactly where you are. Sokoban's core assumption is that pushing costs you your position — delete it and every solution you know stops working.

8. 
   Some lines were meant to be crossedFrpzzd · 7 rules
   LATE [player no start] -> [player tail]
[> player|tail] -> cancel

   Your own trail hardens into wall behind you, and you win by clearing every path and returning to where you started. A Hamiltonian circuit expressed in two rules, with the elegant consequence that the puzzle tightens in exact proportion to how much of it you have solved.

9. 
   StairwaysFranklin P. Dyer · 6 rules
   [> Player|Block No Stairs] -> [> Player|> Block No Stairs]
[> Player|Block Stairs] -> [Player|> Block Stairs]

   The same push, conditioned on the tile it happens on: everywhere else you travel with the block, on stairs you stay behind. One rule written twice with a single term changed — the tidiest demonstration in the gallery of how PuzzleScript wants you to think.

10. 
    Ebony & IvoryGuilherme Töws · 9 rules
    [ > Black | White ] -> [ White | Black ]

    Pushing something into its opposite does not move it — the two trade places. Displacement stops being transport and becomes exchange, so the board's contents are conserved and you are only ever rearranging what is already there.

11. 
    MazezaMMalcolm Tyrrell · 8 rules
    Horizontal [ > Player | Crate | ... | No Object | WallLike ] -> [ > Player | > Crate | ... | | WallLike ]

    Moving sideways shoves an entire row along until it finds a gap. You are not pushing a block, you are operating a row — so a level reads less as a maze than as a bank of sliding registers you have to align.

12. 
    Lime RickTommi Tuovinen · 11 rules
    UP [ UP PlayerHead3 | No Obstacle ] -> [ PlayerBodyV | PlayerHead4 ]

    A snake that climbs. Your body is a fixed stack of segments, and moving up spends one — so the creature's own length is the resource, and the level is a question about how much of yourself you can afford to leave behind on the way.

The degenerate case, outside the ranking. the undertaking by anna anthropy has the shortest ruleset in the gallery at one rule — [ Autoplayer ] -> [ Player Exit ], against a win condition of "all Player on Exit". The game wins itself. It is a conceptual piece rather than a mechanic, and it belongs here as the floor of the scale rather than the top of it.

• TIC-80

  MIT

  240×136 · 16 colours · 256 8×8 sprites · 4 sound channels

  The open one. Code, sprite, map, sound and music editors are all built into the console itself, games ship as single cartridge files, and the community catalogue plays in the browser with nothing installed. It accepts nine languages — Lua, JavaScript, Python, Ruby, Wren, Fennel, Squirrel, Janet and Moonscript — which makes it an unusually low-friction place to prototype a mechanic.

  github.com/nesbox/TIC-80

• PICO-8 carts

  Console is paid & closed

  128×128 · 16 colours · carts export to HTML

  The larger and more famous cartridge scene, and worth browsing even though the tool isn't free. Carts play in the browser at no cost and their source is viewable in the console, so it works as a reading library either way.

  Listed for completeness, not as an open-source recommendation — PICO-8 itself is a paid, closed product. TIC-80 is the one you can fork.

• JS1k

  Archive — ran 2010–2019

  1024 bytes of self-contained JavaScript

  Started as a joke in 2010 and became a serious annual competition before winding down. A thirteenth of a js13k budget, and it still produced playable games — a full colour Tetris in 1024 bytes among them. The demo archives are still up and each entry's source is right there, because at that size the source is the entry.

  js1k.com/2010-first/demos · the successor runs as js1024

• Dwitter

  Live

  140 characters · one canvas · a function of time

  You get a function u(t), a canvas, and 140 characters. Everything is remixable in place, so a good trick spreads and mutates through the site within hours. The #game tag is where people have squeezed something interactive into that budget — less a place to find games to play than the clearest available demonstration that mechanics cost almost nothing and content costs everything.

  dwitter.net

• Ludum Dare Compo

  Source required

  48 hours · one person · everything from scratch

  The Compo is the strict half: solo, 48 hours, all assets made during the event, and source code must be included in the submission — for the Jam track too. Two decades of themed archives, and because the clock forbids scope, entries live or die on a single idea. Filter to web builds and you have a near-endless supply of exactly what you asked for.

  ldjam.com · github.com/topics/ludum-dare

• 7DRL Challenge

  Source not mandatory

  seven days · one complete roguelike

  Build a finished roguelike in a week. The genre's whole tradition is that a run is generated from rules rather than authored, so a seven-day budget pushes entrants straight at the mechanic — and the community norm of writing up what you tried means the reasoning is usually published even when the code isn't.

  Unlike Ludum Dare Compo, releasing source is a convention here rather than a rule. Check per entry.