Very fun game! I saw several dishonered/titanfall like "parallel levels" games in the jam, and I like the idea of having one level with different physics to progress - it kept things fresh. It was also the right length, challenging but not too hard. I also like how satisfying it is to use the submarine after the stress of managing the air.
The controls could have been improved maybe - give an option to jump with space, and make them more precise? I was constatly damaged and I wasn't sure why
The art and audio are simple, but it's impressive that you made a complete game by yourself, and a fun one at that!