i've seen similar ideas a couple of times now, but you definetely pushed it the farthest!
you certainly found a lot of creative ways for dead bodys to be used.graphics and music were spot on, as well!
here are some minor points, that might help (or not ;-)
- i think the hitbox should be a little smaller especially around the head - at least when it comes to receiving damage/hitting spike/edges of platforms. I was getting a lot of deaths that felt unfair/incorrect. also: involuntary head bumps.
- the wall slide gets triggered a little too early for my taste. lots of unwanted wall clutching
- I do prefer a controllable jump height through how long you push the jump button - so just a little hop when you tap it -> high jump with a long button push. it gives you more control imo.
- ok last one: I think you introduced a lot of mechanics, but you didn't really use them to build puzzles. it was like the whole game was a tutorial. some levels where a bit tricky to execute, but I don't recall a moment where I actually had to think about a solution. so instead of introducing a new ideas every 2 rooms, I think the game would benefit from exploring a single mechanic and get creative with it for a couple of rooms, before introducing a new one. (I'm thinking about portal here. which clearly, you did too ;-)
all in all: very strong entry though!