Thanks! There is no sound at the moment, but I plan to add it. The level design is actually derived from the notes of Clair de Lune by Debussy (an easter egg moonshot interpretation) and I intend to add some ambient synth music based on the nearby notes. It's all coming, just wasn't able to find the time before the jam ended.
The game does get difficult. I also plan to add a story mode which will introduce you to a bouncing technique. You get bobbing in the water and hit the thrusters when you're as high in the air as you can get. Allows you to dive much deeper and makes progressing easier. Thank you very much for the feedback!