This Game reminds me of Cell Stage in Spore, Solid 9/10! Also I've noticed that there are assets for a Shark in the source code (standalone download), but I was unable to encounter it, is it possible to play as one?
Yes, it is, at each stage, you have to survive 30 seconds without the ambient getting too dark, if it gets too dark, those 30 seconds reset. The game wasn't meant to be hard, maybe you were just unlucky with random spawns but glad you liked the game! :D
