The concept is cool but there are some pacing issues. The endless-runner-like section before the boss felt kind of drawn out with no real direction or progression since it felt like I was just being hit over and over again with random spawns out of three different enemy types. The semi-transparent boss projectiles were somewhat hard to see and sometimes, I was just shooting offscreen and hoping I was actually hitting something. Consider adding impact sounds upon bullets making contact with enemies. The combat was also somewhat slow, considering how many shots enemies take to die. I would've enjoyed the combat more if I felt like my actions had some impact to them and the gameplay didn't mainly consist of circling around enemies until they died. Overall, it's not a bad game. I think it would be fun once the pacing issues are fixed so that the player is reacting to the game rather than waiting for the game to react to them.