Cave Digger

You're the @, buried in soil. Tunnel through dirt, collect gems until you hit the quota, then race the clock to the flashing exit. Simple — except that boulders obey gravity, and you are the one removing their support.

Controls

• WASD or arrow keys — move and dig
• Walk into a boulder sideways to push it (needs empty space beyond)
• P — pause, T — cycle theme, C — toggle CRT effects, M — mute, ? — help

The rules

Gravity is the game. A boulder resting on dirt is harmless; dig out what's under it and it falls, crushing bugs and you alike. A falling boulder kills — one merely sitting on your head does not. You can push boulders sideways, never up or down, and digging straight down underneath one is the last thing you'll ever do.

Boulders also roll off other boulders and steel walls into gaps, so the cave keeps rearranging itself as you tunnel through it.

• Bugs patrol the tunnels. Touching one is fatal — but drop a boulder on one and it becomes a gem.
• Magic walls (from level two) turn a boulder fed through the top into a gem out the bottom. They only stay lit for a few seconds after waking, so it becomes a frantic dash to feed them.
• Combos: grab gems in quick succession for escalating score.

One HTML file, no build step, no dependencies, no assets.