Switching the movement abilities with powerups is a neat mechanic.  I can tell that with a bit more time you could really make more interesting levels with this premise.

Putting the tutorial and credits in the background works great.  I tend to put off making a tutorial because I'm thinking of something more complicated that plays and highlights things; but that's more complicated than it needs to be.  This is a quick solution that gets the point across.

Very cool idea! Only the game speed could be a little bit faster :)

For me (i think) it took me a while to use the controls, but i knew from the start that the meter looked kinda suspicious

This is really cute! Despite the simplicity and short length, I had fun with this. Being unable to actually move without a powerup, and only charging jumps is a neat game mechanic, and works well with the super cute slime design. I think having the jump charge faster would help the game feel more snappy and responsive, but nevertheless, this works quite nicely.

(Also I found the secret, it was cute to see you added a little easter egg!! Can't believe I was voted out....)

This is fun!