THE GOOD (what i liked, and what stood out for me):
Overall, the game, in my opinion, represents a classic,well made rage game. The art is amazing and "in your face", the gore is great and the levels (oh god the levels) are very, very hard. There are some nice puzzles, and you get a sense of satisfaction solving them. I got stuck at level 3 :-P. I find your taste in music quite nice as well!
THE BAD (what i disliked, the bugs, and other problems):
The game had too steep a difficulty curve, and I found myself struggling only at level 3. The platforming mechanics were also quite clunky and easy to hit the spikes. Usually you want to go easy on your players, by giving things like coyote time or smaller spike hit boxes! I feel like if there were more easy levels, before going to the hard ones, the player-base would get a sense of satisfaction beating the levels.
THE HARSH (stuff that would just make the game better, usually just personal opinion, don't take it too heavily :D ):
There was some minor collision clipping bugs, as in the creatures getting stuck onto the platforms, but you can overcome that by going the other direction. There wasn't much variety in the game mechanics either, it felt too much like a regular platformer. Your idea isn't really that unique, as far as I've seen, a lot of games do a similar thing to what you're doing, so beware of the competition!
OVERALL: GOOD GAME, I LIKED IT :D, id give it an overall 4,2,5