I was walking through the arcade one day in 1980 with my friend Dave and we came across this Cinematronics vector graphic co-op shooter called "Rip Off".
Co-ops were fairly rare and always fun at the arcade and this game was very challenging even with two players, as you tried to protect the little pile of triangles in the center from the pirate ships that towed them away.
Basically a very early tower defense game. I was very fascinated by the fact your ship could get blown up an infinite number of times, as long as you kept at least one triangle on the screen!










