This game has top notch presentation! From the menu animations, to the sonar effect, it is all superb.
The concept is pretty good too! So much in fact that it made me jump from my seat first time that I died from running my sonar.
Now, sound design-wise, it has the seedling of an exceptional work to round off the overall experience. But for a game that is so reliant on sound, it needs a bit more of polish, since it is really hard to hear the growls that are supposed to indicate the 'hunter'.
I also heard the submarine make some sound upon moving, though it is comparatively a lot quieter than the sonar, to the point where I only noticed once I turned the volume up trying to listen for the growls (which I never heard). Also I think I understood that you were supposed to be able to tell distance from a wall by hearing, but I really wasn't able to echolocate that well, so... yeah... The sound mix overall needs work.
Despite all of that, I am completely certain that once the jam ends, fixing those audio issues should be trivial, and would turn this tense experience with rough edges into quite a gem of this site, ready to be discovered by the general public.
I really liked this one. It really has tons of potential.