It took me a few minutes to figure how to get the game going, since the fact that you can press enter to go through doors was in the readme, but after that it's really fun and interesting!
Actually underrated! I really liked the gravity mechanics, and how the bosses showcase the next powerup you get from them.
I managed to beat 4 of the bosses, but I couldn't figure out how to damage the final one. :(
Really good job!