0
The top of the water is 0 and everything under it is a minus number, so a wreck at -24 is twenty-four metres down. The peach tag on the gauge is where you are right now.
Your sub has no engine. Add up everything hanging on it — that is how far you move every turn, on and on, until you change it. A weight pulls you down, a float pulls you up. You have arrived when you are on the wreck and stopped, which means your sum has to be 0.
The rack is up on the boat, so you can only HANG ON at the surface, and anything you LET GO is gone for good. Don't stop on a mine, don't hit the sand, and don't run out of air — every tap costs a puff.
There is no undo. ↻ at the top starts the dive again. Your score is the clock, running across all ten dives, and it stops while you are reading a message.
On a laptop: space to carry on, R to start the dive again, F to fill the tank and E to empty it.