Not really sure how it fits the theme, but the game overall is really nice and well-polished. I loved the simple graphics, and the sound effects for everything fit really, really nicely. Using the background as the health is just perfect.
Honestly, the only issue with the game is that there's no invincibility frames after you get hit, which makes it feel really unfair when you get hit like 3 times back to back within a second. Were it not for that it'd be a lot more fun.
Still overall really fun, though!