Spaceship

In this game, I developed a space combat. I have a spaceship travelling in the space from left to right and there are enemies approaching the spaceship. The task is to destroy the enemies and get points. The spaceship has limited bullets in 3 levels. In level 1, it has 20 bullets, level 2 15 bullets, and level 3 10 bullets maximum. As the spaceship fires bullets, the number of remaining bullets decreases one by one. Until there is no bullet left when the spaceship cannot fire any bullet. There are some energy objects coming toward the spaceship. If it hits the energies, it gets 3 bullet boosts.