Oh man, this game is unpolished in so many ways, yet somehow that gives it charm haha
A few little things I noticed:
- if you shoot a hamburger to the right, then press left, the hamburgers will start moving left
- falling off of the clouds into the pit just makes you land in the pit and you don't die
The art might be childish, but it's so random that it's more creative than anything else and looks kind of neat, actually XD
And if you're planning on doing tile-based platformers, take a look at the work Nifflas does. It's all very simple pixel art, but he puts so imagination into it that it just works well. :) Knytt Stories in particular comes with a huge database of tilesets (made by various people, not just Nifflas) in the level editor that are sure to give you ideas of how to make some nice tilesets.
Also! Love the music :D
If you're planning on continuing on this particular project, my suggestion would be to fix up the bugs, then just expand the area and continue making lots of wacky little objects here and there. :) Right now what makes your game fun (to me at least) is that it's interesting just to look at and listen to, maybe not for the gameplay but more of an experience.
EDIT: Forgot to mention that for most platformers (especially ones with collectibles) it's important to be able to get back to anywhere in the level you were before in case you missed something. In your level right now, after you jump off the little cliff you can't get back up, meaning you're confined to the small area after the cliff.