I played it and I like the particle effects and the idea behind it!
I believe that the weapon rotation needs to be faster, or the enemies slower, since I usually lose because I can't get to position fast enough. The weapon is also not very forgiving, you need a perfect shot to kill the enemy.
Since it seems like a good game, and if you want to develop it further, I would add more weapons, different enemies and maybe have the gravity of the enemies affecting the bullets.
Good job! Keep it up!