Not going to lie, I struggled a good bit on this one. Something about having to prep the fireball and click again to fire tripped me up. I think part of the reason is that the game is relatively fast paced, and having to prep the fireball first was more of a hinderance than a strategic benefit. Also, when I tried to reverse the fireball while it was in flight, the graphic flipped but the direction remained constant. I think I would have enjoyed it a lot more if there was an option to fire the fireball immediately, without any prep involved.
The only other criticism I'd have is that the jumping felt really floaty, but that might have just been a design decision given how much stuff you're trying to avoid.
The one hit kill felt punishing, but that can work if you have smaller levels. Unfortunately I didn't progress far enough to find out.