Could really use more sound and music, but it’s okay - the punch being able to be retriggered as often as you click really makes it feel “video gamey” which isn’t necessarily a bad thing, but I think it maybe is for what it seems like you’re going for. I actually found it pretty easy and straightforward once I realized I could just hold space to swim. Any time a game has me holding a button down constantly it always makes me ask - why not just do the thing automatically? Not saying constantly swimming forward is the right choice for the game, but I think that’s something worth considering game design wise.
Cool idea and good work in getting it together :)