THE original shmup. Blast rows of aliens, shoot at a UFO occasionally, hide behind shields, things get faster the fewer enemies are on screen. Rinse and repeat until you lose all your lives.

In reality, this game is incredibly simple, but I'm giving it full marks just for its legacy and for having the cutest little alien sprites I ever done did see. I have a big soft spot and love for this game and I won't stop appreciating it.