Short and little game about shooting a horde of enemies. I would say the color contrast in things like the timer and the enemies with the background needs to be higher to be comfortable for the player. Also, the game becomes very trivial once you realize you have virtually zero cool down between shots.
I did like very much the detail of the larger enemies actually staying alive for a bit once they hit the spaceship and dealing continuous damage to it.
All in all is a very simple but solid game to have done in less than 100 lines of code. Great Job!