Saw your post on the Unity2D subreddit and had to give it a shot. It looked really fun and it is! Love the look of it and I'm always a fan of these types of games.
I got to about 130 on my first try (forgot the time) but got screwed by the first boss.
Would be really awesome if there was some kickass music blaring in the background and some sound effects, too. But it's a prototype so it's fine. And for a prototype this is really good.
Keep it up, hope you continue developing this game.