A fun homage of a fun game! The sprite work is well done and cute, and it's very easy to read what each enemy type is supposed to do. The level up mechanic is incredibly interesting and a nice take on a usually EXP- or wave-based sub-genre. The hits felt good and meaty. I do just have to reiterate that I really liked the way leveling up works in your game!
My only bug report here is that the "slide in and out" black screen only covers about 3/4 of my screen while leaving the right half (and ~150px of the bottom of the screen) uncovered. To note, I played the game using the web build/FireFox and I am on a curved, wide-screen monitor.
Great job, and a fun, re-playable experience! I could definitely see myself playing this more if you decide to build it up further.
- ImPasta/Mica