I really enjoyed this one. at first, the controls felt a bit strange, but once I realised how they worked, it felt very satisfying. Finding the exit took a few tries, but I did end up finishing and having fun! The game froze for quite some time while loading the leaderboard, I genuinely thought it might have crashed - but I can't tell if that's an optimization issue or just my potato of a pc being what it is.
You mentioned overcoming your fear of sound design with this one - I think you did a good job. The scenario alone is anxiety-inducing for a lot of people with all the stories about cave diving, and the sound design fit the atmosphere perfectly, imo.
Also, for whatever reason, my brain got nostalgic feelings from seeing the little sprite swim - I think because in horizontal position it digs up some memory of Commander Keen 4's underwater level for me, personally.
Overall, was a really enjoyable experience for me (: