Really solid, nice! In particular, the audio was fantastic. The scripted sequences felt polished and the writing was entertaining. The graphics were charming and definitely suited the tone of the game, although I think the anti-aliasing was a bit rough at times.
(Spoilers) I didn't get the hints that the fish were robotic, probably because I either wasn't paying enough attention or I chalked it up to a quirky writing/art style. I also didn't get any hints to the sub being run on human energy. Anyway, this meant that I didn't have a clue as to what nefarious things the narrator was up to. So when the plot twist approximately said "yes, the fish are made of plastic" I felt like it expected me to have suspected that (or thought I should've), which I didn't. I lost some immersion as a result.
But yeah nah definitely a strong experience. I think there was an impressive variety of mechanics for a jam project. Nice job.