That was pretty cute. I like the little blocks and the movement and jumping are really responsive.

The first phase is really easy as you can stand in teh corner and shoot everything on the right. Being able to shoo right or left when the mouse is either to teh right or the left of the character would also be more intuitive than shooting left after moving left.

All and all, a neat little game :)

The game seems to have potential, but it lacks warning signs for when and where a new enemy is going to spawn. I lost far too many times because an enemy spawned next to me or beneath me after a jump, and I crashed into it before I had a chance to react. I couldn't get to the boss because of it!

Good job, but there's room for improvement.