You are a recent enlistee in the Earth Defense Corps. For the past six weeks you've undergone grueling and intensive training. Now you stand at attention, nervously anticipating the most critical section of your training: Attack/Counterattack! In preparation for this task you've read, reread and memorized the SPACE INVADERS manual.

"Okay, kid, you're on!" barks your commanding officer.

Quickly you climb into a laser tank. A second enlistee follows you. You each settle into deep, leather seats. With a soft whirring sound, the automatic hatch cover closes overhead.

As your eyes adjust to the dim light of the laser capsule, you begin to make out the controls. Mentally, you check off each knob, dial, button, and display. For the next several hours you and the other enlistee with operate these controls to defend your planet in an attack simulation.

The screen in front of you lights up. A column of bomb-dropping aliens advances toward you. What next? For a second your mind goes blank. Have you learned your lessons well? No time to refer to the manual now. Your commanding officers are watching and it's your show.

(credit: Atari; excerpt from original game instruction manual)