I liked the tile set that you used and the main character  was definitely fun looking. The player did feel a bit floaty when jumping and the shoot button was also bound to the jump button.  With that being said, the shooting could have been remapped to mouse button 0. The Invincibility was the only way I really killed the enemies despite some of my shots going through the walls

The buttons should really be resized, as they take up the majority of the screen. Pressing space bar both jumps and shoots, making combat really awkward, as they should be different buttons. Other than that though, it's an interesting game!

The instructions said tapping the screen would fire a shot, but this isn't the case. Pressing spacebar makes the player character shoot and jump at the same time, making combat awkward. The sound mixing could use some work. I also got stuck on walls at some points.