Cute little game! Love the little rat guy.
Gameplay was pretty fun. It was a little weird that after a while, fireballs just stopped spawning and and only after all the fireballs health drops showed up. Maybe having fireballs spawn endlessly (and despawn at some point to prevent lag) would be interesting?
Cute sprites, but I think they could be a little more consistent by balancing the pixel density. Also, I think sound effects would go a long way here!
Very cute ending screen! Overall, a nice little entry, well done.