I had quite a lot of fun playing this game, and honestly i feel like unlike some other games, you made something very "classic" but it ends up working really well. The interesting parts is that there isnt a singe bad thing: the music is good, the graphics are cool, the game is longer than most other jam games, each level is unique with different background and ennemies. The only "problems" are minor: ennemies have quite a lot of health, sometimes some walls are a bit missing (at the end of the 1st level for example you can die to the right if you dont know you have to wait), as well as the few problems you couldnt fix because of time (red music too loud, although its not that bad, health not showing in yellow level).

Overall its a simple and funny game, and i think you should do more jams, with a bit more experience your game would've been perfect!

Btw i think you are using game maker studio 1, you should use GMS 2, the free version is enough to do small games for a jam.

Anyway I'd apreciate it if you could try out my game, and most importantly leave a comment for feedback (and rate the game also)