Astro Fighter
By today's standards, Astro Fighter isn't anything to get excited about, but in 1980, this game was, like, ohmigod, so totally bitchin'. At a time when it was a big deal for a game to be in color, Astro Fighter featured scrolling animated backgrounds, enemies that looked just like TIE fighters, and a challenging twist that sucked up quarters faster than the opening act for the late-night donkey show.
Gameplay: You have to survive five waves of formation attacks from various enemies, which is pretty standard for a 1980 space shooter. However, Astro Fighter sets itself apart from the pack with the addition of a fuel tank that can only be refilled if you complete all five waves of attacks. Run out of gas, and your game is over. And if a single enemy makes it past your ship, the entire squadron will reappear at the top of the screen for another attack. The more ships you shoot, the faster the remaining ones move, so you'll have to stay focused. No singing along to "Open Arms" if you want a high score.
After you've blasted through all five waves, you'll face off against the Master, who can only be wounded by a shot in his one terrible eye. Beat him, and you'll refuel for another round of more difficult attacks.