
Replicube
OfflinePaidest. 2025★4.6 (119)Write Lua to procedurally recreate a target 3D voxel object using as little code as possible.

Marvellous Inc.
OfflinePaidest. 2024★4.6 (58)Program corporate robots in a tongue-in-cheek assembly to run a dystopian megacorp’s operations.

Oort
OnlineFreeest. 2021★4.6 (78)Write Rust to pilot a fleet of spaceships through combat scenarios and climb the tournament leaderboard.

Battlesnake
OnlineFreeest. 2018★4.6 (167)Build a web server that controls a snake, then battle other developers’ snakes in a multiplayer arena.

Flexbox Froggy
OnlineFreeest. 2016★4.6 (421)Write CSS flexbox properties to guide frogs onto their lily pads — the canonical way to finally understand flexbox.

SQL Murder Mystery
OnlineFreeest. 2019★4.6 (264)Solve a murder by querying a city’s database — interrogate tables, follow leads and write the JOIN that names the killer.

Screeps: Arena
OnlinePaidest. 2022★4.5 (142)The same JavaScript brain, distilled into discrete PvP matches — write the AI, drop it in the arena, and let it fight.

MOLEK-SYNTEZ
OfflinePaidest. 2019★4.5 (168)Synthesise molecules on a low-level machine in a bleak Romanian apartment. A lean, cheap successor to SpaceChem.

Robocode
OfflineFreeest. 2001★4.5 (274)Build a robot tank, code its brain in Java or .NET, and drop it into the arena. The classic that taught a generation to program by battling bots.