ls20 — ARC-AGI-3 game guide

Full spoilers for this public game. Play first if you want to discover its rules yourself.

Transform a key into the required shape, color, and rotation to unlock an exit door, under a hidden step budget and three lives per level.

You carry a key made of colored pixels and walk it over special tiles to change its shape, color, and rotation. Reach the door with the key matching the lock, before you run out of moves. Running out costs one of the level's three lives; lose all three on one level and the whole run ends.

Controls

Level by level

Level 1

ls20, level 1
  • Up, Down, Left and Right move your block one cell (5 pixels). Your block is the square that is orange on top and blue underneath. There is no clicking and no undo.
  • Walking into a wall (the darker gray areas) leaves you where you are and still costs a step.
  • RESET restarts the level: you, the key, the pickups and the doors all go back to the start, the step meter refills and all three lives come back.
  • Each door is a black box with a picture of the key it wants, drawn in the right shape, color and rotation. Walk onto the door while your key matches that picture exactly and the door opens. When every door on the level is open, the next level loads.
  • Reaching the last door on the move that empties the meter still counts: the door check runs before the life is taken.
  • Your current key is shown in the black box at the bottom-left of the screen. It changes only when you step onto a key-changing tile.
  • The rotation tile, a small white and light gray glyph, turns the key a quarter turn clockwise each time you step onto it. Step off and back on to turn it again.
  • Walking into a door with the wrong key does not open it. You stay put, the key box flashes white for a moment, and the move costs no step.
  • The yellow bar along the bottom of the screen is the step meter, 42 units on every level. Each move uses one unit on levels 1, 4 and 6 and two units on levels 2, 3, 5 and 7, so 42 or 21 moves. Spent units turn dark gray.
  • Three red pips at the bottom-right are your lives for this level. When the meter runs out, you lose a pip, the whole screen flashes yellow, and you start the level over from the beginning with a full meter. Losing the third pip on one level ends the game. Every new level starts with three again.
  • Losing a life also resets the key to how it started the level, brings back every pickup you used, and closes any door you had already opened.
  • Level 1 only: when a tile makes your key match the door, white outlines flash around the key box and around the door for a few frames. That move also costs no step.

Level 2

ls20, level 2
  • Small yellow rings are step pickups. Walk onto one and the step meter fills back to full, the ring disappears, and that move costs nothing.
  • From level 2 the meter drains two units per move (levels 2, 3, 5 and 7), so those levels give you only 21 moves per life.

Level 3

ls20, level 3
  • The color tile, a small patch of blue, green, red, orange and white, changes the key's color each time you step onto it, in the order orange, blue, green, red and back to orange.
  • Launch pads: a cell with a light gray bar along one edge. Step into it and it flings you the other way from the bar, sliding you and the bar across the room to the last cell before a wall or door, then the bar springs back. The step into the pad costs a normal move and the ride is free.
  • A launch skips everything it slides you over. Only the cell you stop on takes effect, so a tile or pickup there still works.

Level 4

ls20, level 4
  • The shape tile, a small white glyph, changes the key to the next of six shapes each time you step onto it.

Level 5

ls20, level 5
  • Some key-changing tiles move. Each time you move, they take one step along a hidden path, back and forth along a line or around a small square. If your move is blocked, they stay put.

Level 6

ls20, level 6
  • Two doors, each wanting a different key. You can open them in either order, and the level ends when both are open.

Level 7

ls20, level 7
  • Fog: everything more than 20 pixels from your block is black, doors included. The key box, the step meter and the lives stay visible.

Mechanics

The key is represented as a distinct group of pixels, typically located in the bottom-left area at the start of each level. You must move your player avatar over transformation tiles to change the key's shape, color, and rotation to match the lock. The door does not require a specific trigger action; simply reaching it with the correct key configuration will finish the level -- though level 6 has two separate doors that both need solving in turn, not just one. Every level also runs on a hidden step meter of 42 units, drawn as a bar of pips at the bottom-left of the frame. That is not 42 moves everywhere: levels 1, 4 and 6 drain one unit a move (42 moves), while levels 2, 3, 5 and 7 drain two (21 moves). Running the meter out does not end the level -- it respawns you at the level's start with a full meter and costs one life. You get three lives PER LEVEL, shown as three red pips at the bottom-right, and they are restored every time a new level begins. The THIRD loss on a single level ends the entire run, not just the level. RESET also restores both the lives and the step meter, because it re-runs the same level-setup routine, which makes it the only mid-level way to buy a life back -- a human win on 2026-09-15 used exactly that on the final level, one pip from losing the run. The final level adds fog-of-war, blacking out everything beyond a short radius around you. A lost life also puts the key back to its starting shape, color and rotation, brings back every pickup you used, and closes any door you had already opened. Other pieces the text above never named: from level 2, small yellow rings refill the step meter when you walk onto them; from level 3, light gray bars on the edge of a cell launch you across the room until you hit a wall; from level 5, some of the key-changing tiles slide back and forth along hidden paths, one step each time you move. Walking into a wall still costs a step, but walking into a door with the wrong key does not.

Notes and caveats

Corrected 2026-09-12 after a direct, adversarially-verified source read: added the hidden step budget, level 6's second door, and the final level's fog-of-war, none of which the original write-up mentioned. Corrected again 2026-09-15: that pass got the life system wrong in both directions -- the three lives are per LEVEL and refill on every level change and on RESET, and the THIRD loss on a level ends the run, not the fourth. The 42-unit meter is also only 42 moves on levels 1, 4 and 6; levels 2, 3, 5 and 7 drain two units a move. Both corrections are cited line by line against ls20-9607627b/ls20.py and confirmed frame-by-frame on a human winning recording in docs/2026-09-15-ls20-lives-and-step-budget.md. That win, added to resources[] the same day, is the first replay listed here on the current build -- the older ls20-fa137e247ce6 links, including the video, are from a build that has since been replaced, and had EIGHT levels where this one has seven. Both listed replays are human; neither is an agent run.

All official game guides · The Slippery Seven · Human and AI results