Here's my little composition. You play a free diver. The twist is that you have to hold your actual breath while holding a button. It's a bit gimmicky but if you follow the rules, it's kind of fun. I didn't manage to reach the deepest levels.

Instructions

Press "spacebar" while holding your actual breath to reach your goals. Release "spacebar" when you're out of air and try to improve your apnea.

Links

LD Page : https://ldjam.com/events/ludum-dare/57/apnea
Itchio (Web) : https://julienlussiez.itch.io/apnea