Very interesting take on the metroidvania genre, find new power up, explore new area, repeat, very nice.
I feel like the first spider like enemies would be easier to read if they were less spiky on the top, my first impression was that I would die if I jumped on them.
Maybe make the slime a bit less slippery would help for precision jumping.And add an indicator for the high jump, it's nice that the slime squishes but I found it hard to judge how high I would jump.
Otherwise, a very nice entry and an original interpretation of the theme! Good job!