There are so many levels! I'm glad I got to the end =) Here's my feedback:
+ I like that some levels are more vertical than others, and the fact that the first level has multiple paths.
- The parry mechanic could have a bit more lenience I think (its a bit too precise). Some visual feedback when you hit it would be nice (maybe just a quick color change and an sfx maybe?)
+ There's a lot of enemy variety, which is a nice touch.
- Some enemies shoot off-screen, which can be a bit annoying at times. However, you can also shoot them offscreen so it's all good I guess haha.
+ In a way, the epic music sets a funny note to already comic tone of the game.
I think a visual upgrade would do wonders for a game like this. Good job!