A very popular arcade game of the 80s was Galaga. It was the sequel to Galaxian and was released in 1981 by Namco.
I’d call Galaxian a typical space invaders clone but taken to the next level where the aliens have much more movement when flying around.
Galaga goes one step further. The aliens fly in more daring flight patterns but are in no way random. Regular players know where to sit so the aliens can be shot when they initially appear.
A cool, new feature in Galaga is where a “boss Galaga” attempts to capture the player’s fighter using a tractor beam – if successful, the fighter joins the formation and must be freed by the player (using another ship and costing him/her a life), enabling him/her to control two ships simultaneously. That doubles the firepower but if you miss in capturing it, there goes (in effect) two lives.
Play it here: