The game itself is fun, I just don't like the controls. I think having either just the arrow keys (left right for moving, up for jumping) or using wasd (a for left, d for right, w or space to jump) would be better than to mix arrow keys with space. It is my opinion, but that feels weird to use.
Since this is a platformer, you could also have a look at this, which is a game here on itch.io to explain the fundamentals of platformer player control.