The idea has merit, and I like the art style overall and think it makes the game stand out. I particularly liked the feel of the spider's jump. Going from the slime, to the spider, to the psychic kid also felt like an interesting progression of power.
However, I do feel like some clarity was sacrificed for the aesthetic. Personally, I argue text legibility should come before a unique style every time. Not much point in trying to achieve a particular style if that style can't be (or is tough to) parse.
I also feel like this game could have done away with any kind of traditional health system. Trying to be damaged is an interesting twist, but not if the game only requires the player to just sit there. I personally found the best way to die to the blue kid was to get on his head and jump every so often. Rinse and repeat. If it's too easy to take damage, and the player has too much health, then the game becomes a mater of grinding easy hits with little interesting decision making or reaction.