A time travel 2D platformer that compresses down to just 15 KB.
Timeline
2026
Role
Team
Team
Alan Dong, Michael Li, Seunghyun Bae
Tools
JavaScript, HTML5, Canvas
Echo is a 2D platformer where you rewind time to leave a “ghost” of your past run. You and your clone exist in the same space: you can bounce off your past self to reach higher ground, trigger switches in one run and walk through the door in the next, or use the clone to hold a button while you cross the gap.
We built it in 24 hours at TartanHacks 2026 for the AppLovin track, which required the full game—code, assets, everything—to fit in 15 KB. The size limit forced hard tradeoffs: no image assets (everything is drawn with canvas APIs), hard-coded sound, and aggressive code shrinking. The mechanic had to carry the game.
Along with my teammates, (Alan Dong, Michael Li, and Seunghyun Bae), we won the AppLovin track.
Example level. Your past run is recorded as a clone; you can bounce on it to reach platforms you couldn’t get to in a single jump.
Gameplay clip showing the time-rewind mechanic and platforming.
Some levels are mostly dark. Your “light” clone from the previous run shows the path and where to land; you plan the next run from what you see.
A level where you can't get up to the top without bouncing on your past self.
A playable demo is linked in the sidebar.