One of the most complete games I've played in any game jam. Well-balanced and pretty polished. I agree the player could be a little faster, but I also think it's part of the underwater feel to make him a bit slow and I did get used to it. Overall, great controls, great visuals, a variety of fun challenges, good sound. Sadly, I couldn't proceed once I got to the shipwreck, as I'd blown up the two bombs earlier, so do consider making things a little more idiot-proof ;) For a bit more polish I would show the controls in-game at the start (i.e. "use e to interact" first time getting to the submarine), and the fact that WASD controls switch to arrow keys at the submarine menu feels a little odd.
Story was the only thing that felt a bit lackluster to me. The atmosphere feels mysterious and creepy and you're completely isolated, but finding messages every so often from my crew that seemed alive and well kind of broke through that feeling. I think it'd be more mysterious if you found bits of pieces of, perhaps, their gear, or their shipwreck, or other visual elements that hint at their fate without spelling it out literally, as I think the lack of clear answers and communication feeds more into the feeling of isolation and the mystery of the ocean. Just my thoughts.
Also, was kind of wishing for a gigantic sea monster to show up.