Infiltrate (Atari 2600, 1981)

Infiltrate is the spy game of high stakes espionage. In the vein of Elevator Action, you play a secret agent infiltrating a top secret fortress. You must maneuver through a maze of corridors and elevators to retrieve the secret documents located on the top floor. Make your way back to the ground level and the mission continues. 

But watch out. Enemy assassins are programmed to shoot you on sight, and they can ride the elevators as well. Good thing you have a laser gun as deadly as theirs. Duck to avoid enemy fire and return with some fire of your own. Kill one assassin and another will appear to take his place ... how long can you survive?

There are 12 variations of Infiltrate -- six one-player games and six two-player games. You can choose the speed and intelligence of your enemies, and there is also a variation in which the assassins are invisible. 

Setting the difficulty switch in the 'B' position will limit the range of the enemy lasers. The 'A' position will allow their lasers to travel the width of the screen.