Nice Game but very hard !
The projectile following the mouse makes it very hard to actually hit something since you're constantly moving.
For feedbacks:
The health bar placement made me think it was the enemies health at first (maybe center it on top of the screen to avoid confusion ?).
The player controller felt a bit weird and hard to be precise with to be honest.
The light green of the alien also felt a bit off against the rest of the color palette.
Appart from that its a pretty nice game. with a bit of difficulty balancing it can be very fun.
Good work :)