I liked how the porcupines had their projectile attacks you had to avoid, but when a bunch of them are grouped up, it can be REALLY hard to beat them when they're all shooting on a cycle, you have no opportunity to get in closer.
I was able to make it a few waves (or at least what seemed like a few waves) but I don't think the heal button ever did anything? I was holding down K and nothing seemed to happen, I don't know if I'm supposed to only heal when the bar is full or what.
The graphics are cool, I'm normally not a huge fan of scanline filters but I think it worked here. When you load the game, what assets are you actually loading? I ask because the first time I did something that required a new sound effect (e.g. the first time I jumped, the first time I attacked an enemy) the game noticeably froze, which to me seems like you're not loading sound effects at the start of the game.