Really impressive! I loved the art, sound and UI. I really like the title screen being a tutorial level, it helped me understand the game before I even got started.
Feedback wise, i think the doors as the end of the level could use some work. I didn't notice the first one appear so was stuck for some time. And kept finding myself back tracking a lot because if there were multiple doors I wasn't sure which one went where. In the power up room I also jumped into the first powerup before I realised that if you stand under them it would tell you what they are.
Very good though, a level of polish I would love to achieve for my own games.