Protect the Starbase!
My then boyfriend and I would hit the arcades after his classes. I'd watch him play other games for a while and we'd save Xenophobe for last. If we were lucky, they'd play, "Pump Up The Volume" by M.A.R.R.S. and we'd be in fighting heaven! Afterward, we'd grab some cheese steaks and fries, totally satisfied in our lust for alien destruction.