I enjoyed the design and ambition of this game. I also liked the simple pixel art and 8-bit sound. Exploring was a good amount of fun. The main mechanic has a lot of potential that you could build upon. I wish I could fire the projectiles faster, though. With how slow it was, I found enemies to be very frustrating, and using the bullet for exploring to be kind of boring while I waited for the cooldown.
A minor and very fixable complaint, though. Well done.