Polaris

Polaris is a Missile Command clone.

In contrast to Missile Command, in which the player controls three anti-ballistic missile bases and protects cities, the Polaris player controls three submerged submarines and seeks to protect islands.

The real-life Polaris is a submarine-launched cruise missile with a nuclear warhead; and while it cannot serve as an anti-ballistic missile, the parallel is otherwise obvious.

The game required the player to manipulate a joystick (analog), mouse, or trackball to control the cursor, but firing was accomplished not by using the built-in fire buttons of these input devices, but instead by using three keys from the CoCo keyboard, one for each of the subs. Since the standard Radio Shack joystick was so light and meant to be held in the other hand, Polaris players sometimes hugged it between their knees in order to keep it still while using their other hands to fire via the keyboard.

Cartridge CoCo 1 4K Keyboard and Mouse