I was honestly surprised by how good this game feels to play, which is all thanks to the sound design. Weirdly fitting crunchy rock music plays while your character constantly utters retarded sounds when jumping, falling from a great height or taking damage. Shooting your gun and killing enemies has appropriate feedback, and for some reason you just need to collect every single one of those pizza slices just to hear that crunching sound again.
Where the game feels weak is the level design. It was only by the fourth and final level that everything started to really click. The first level is an annoying keycard hunt, the second a mind boggling pachinko machine and the third just felt like filler.
I understand that level design probably wasn't the point of the demo (and maybe not even the final game given the parody-like nature of the whole thing?), but I'd consider trying to tighten up all of the levels with more condensed sections of platforming, combat and minor puzzles.
Elements like the flamethrowers in the last level should be first showcased in a safer environment, I always got hit by the second one because I hadn't gotten used to how slowly the flames move. The shooting enemies are way too aggressive and difficult to dodge, I had to memorise their positions to avoid taking too many hits.
The texts/voice clips uttered by the enemies are cute and fitting, but you might want to consider changing to a font that matches the pixel size of everything else. Reading the small mixelated text is difficult.