Not a bad game concept but heres some advice from a fellow game dev to another
For the controls screen I would add more information other then just displaying the arrow keys and leaving it up to the player to figure out
Maybe figure out a way to by pass a single small slime other then jumping or maybe add that info into the controls page.
Other then that I liked the game play it was clean and preformed well.
Hope this helps. Can't wait to see the final product :3