The file
Galaxian's sequel and the perfect version of the idea. The boss Galaga fired a tractor beam that took your ship; if you shot the boss on the next pass you got the ship back as a second gun, side by side.
The challenging stages, where nothing shoots back and you just try for perfect, are the arcade's version of a breather. Galaga never really left; the cocktail-table version is still in the back of the pizza place.
Sources: Wikipedia — Galaga
