If this was your first game, then I say congratulations. It was simple but functional and had multiple stages.
I always like to give constructive feedback when I can so here are some points I noted:
1. I think what I liked best was the simple visual design with the lighting effect. It would have been even better if: the enemies cast shadows as well, the enemies could not be seen if they were in the shadows so they could sneak up on you.
2. It seemed the hit detection was buggy as the bullets passed through the enemies and sometimes they took 1 shot and sometimes they took 5 shoots to take 1 health/colour off them. I would also probably have made the shooting hold to fire rather than press.
Overall, I'd say be proud