Missile Command II © 1981 Atari, Incorporated.
Unreleased prototype. The game went through many iterations and cabinet designs, and failed focus group tests time after time over a period of a year. The game was cancelled due to these problems.
Picture of Missile Command 2 lab prototype, using mirrors to project the monitor onto two sides for two player simultaneous action. Courtesy of atarigames.com - Design, focus group, and collection documents of the game can be found at Atarigames.com.