First off, great job finishing your game! I think the movement mechanics were very creative, and the fact that you have to both avoid the enemies and your own bullets is very interesting. I'm sure you may not have had time to add it in yet, but some nice maybe 8-bit background music would be a nice touch to this style of game. I do think that it would be really cool to add item drops when you kill enemies, like things such as healing items that restore some of the player health, and maybe an item that gives the player a shield bubble that absorbs one hit of damage before popping. Enemy variety would be really cool too, like maybe adding an enemy that only moves via teleporting from one spot to another? Could be something cool to look into. Otherwise, you've got a good start to your game so far, well done!