The game is quite short and simple to pick up and play. Some sort of indication of how to play would have been nice, though. As a tech demo it's alright. As a proof of concept I feel like it should have had perhaps a little more to show where the game would go (would it stay silly? would it be more serious in nature? would there be stages of difficulty? different enemies? puzzles to overcome?)

The gameplay was smooth and ran fine. It was also pretty fun to run around and shoot enemies with random 'guns'. Overall the concept is sound and it runs well, but it might need a little more to flesh out where you'd go with the game.

The purple shots are too hard to see. 

I'm not sure how this is different from nuclear throne. You even used a similar font, font wiggling, player shot and cloud effect, from the looks of it.

I get that placeholder art can be useful for finishing a prototype, but a bunch of rectangles with letters would've been a better choice. The small window doesn't hide the fact that your guns are a plus sign, a child and a treasure chest. Also, your sprites seem to have a level of anti-aliasing not present in your tiles. That's not good.

Well, aside from being confused at first why what looks like a child is my weapon, I had fun, though it was very very short :(
(unless I am missing something, it is just that first level right, I didn't see any stairs or anything)
Definitely has potential!

It has potential, just need a little bit developing and patience.