Very nice game!
I really liked the use of the primary elements for both spell-casting and puzzle-solving, very creative. I especially like the cauldron bringing it all together. Not too short, not too long, the perfect length to showcase all the abilities and mechanics, a lot of potential for future levels!
Loved the artstyle, simple blob doing blob activities! The jump wind-up is a cute touch, though it made the movement a little less sharp, which is okay, blob is clumsy!
I wish there was a way to switch around movement and ability use between WASD and arrow keys, but that's asking too much of a game jam game, my game also has unconventional keybinds and no way to change them for now…
Also, I kept thinking that the thin wooden platforms are one-way and bumping on their ceiling, but that's more of a skill issue :) I know there's a simple way to solve this in Unity with one-way colliders, there's probably something similar in Godot, I don't think there's any downside in making those platforms one-way.
Great job!