The whole look and feel of your game is very impressive for 48 hours worth of work. Simplistic goal, decent pixel art and a nice difficulty curve that welcomes all types of players, but pushes them to perform well. A nice technique of yours that I noticed was that the music doesn't reset after your die. It simply pauses and resumes once you're back. It creates a nice stream-lined feel that doesn't completely halt the immersion nor does it create frustration.
I don't want this next part to affect your overall score because this may be just me and my wonky computer, but I feel this should be noted. When controlling the character on stage 3 with all the jump-biting, I realized the controls were locked during the biting animation. This caused many water and eel related deaths. Also (on the same 3rd stage) just biting while moving seemed to make the character jerk forward and I couldn't correct the movement. Those are the only noticeable hiccups I found. Let me know if that was your intention or if my computer needs a solid slap to the processor.
Thanks for the really neat game.