Glaxxons

Glaxxons is basically a Galaga clone, with some notable differences. First of all, your ship can not move only at the bottom of the screen, but also to a certain degree in the vertical direction. Furthermore, you can only fire one shot at a time. If you press the fire button repeatedly, the last shot fired disappears. On the other hand, the enemies' shots are target seeking. Also, your ship isn't destroyed on contact with enemies or bullets. Instead, you have a power bar that decreases for each hit.