I like the idea of simulating actual forces on a submersible, and having that be the basis of the game, and I think it could be better implemented if pressure damage was a function of depth and time instead of just depth.
Also, for short jams, it's important to not let scope creep affect development. This game has two distinct sections, one on land and one in water, the first isn't really the main focus, yet would have taken a significant amount of work to create (setting up controls, physics, assets, etc). Try to keep your focus as a developer on fully developing main part of your game, and branch out from there if you have time.