Well done, It was nice and fun, It would have been awesome to see the player and the enemies bigger on the screen so it would have a dominant scale over rapidly moving background details.

Good job! The only thing I could think to add/change is some sort of either audio/visual indication for when you get hit or when you lose a life. I think the background could move slower too, it's get a little hard on my eyes. But overall this is a fun & simple game!