Big news for slime-heads, I don't think you can call yourself a slime fan if you skip this. I thoroughly enjoyed this game! Great job on the movement, all of the abilities are fun and interesting, and they all feel great. I had a lot of fun playing around with switching ability in mid-air. I also like that the game gives you a triple jump off the bat, it emphasizes all of your different movement options.
The game could use a pass for polish. I noticed a few times where the camera limits didn't work or track my slime, and I couldn't always tell what were entrances to places until I was on top of them. Combat is also a little rough, I couldn't always tell when I was being hit vs when I was hitting other things.
None of that ever became unmanageable though. Watching your slime grow over the course of the game is super fun, too. Great entry!