Galaga

A shoot-em-up in which the player controls a 'Fighter'
spaceship and must defend the home planet against the 
hordes of alien invaders called "Galagans". The 
Fighter can only move left and right along the bottom
of the screen. Galagans fly in various formations 
before forming troop lines at the top of the screen. 
Once all troop lines are formed the Galagans separate 
and start attacking the player's Fighter.

Developed by Namco