Unusual cover image, but the screenshots made me interested. You can still work on that right now.
The idea is solid! The artwork is decent, and the sound effects are pretty good.
I do not understand the spiky guy, and I gave up from there. Invest some time in making a simple tutorial for each character.
The main things to work on next time: Test to make things less janky. Add short tutorials. And the biggest of them all: don’t make puzzle platformers, unless you just started out, then you’re fine.