Nice concept, but the physics was kinda flawed. With 0 air control, it's just aim and pray. And the fact that the player is sliding around like everything was covered with ice doesn't help either. But yes, the biggest issue is the lack of checkpoints. Reaching the 3rd torch, then falling back to the bottom worked for Getting Over It, because there at least you can partially block your fall, and physic is a lot friendlier, allowing huge jumps if you get the hang of it. Here, not that much.
And the charging of the fireball wasn't useful either. I'm not sure if any of the gaps would have been easier to overcome with a half charged fireball for example.
Anyway, nice start, with a few more refinements it could be a pretty decent game.