The computer keys were arranged in alphabetical order and the computers ran on tokens.
Tokens were 3 for $1 in 1980. Children could play for "up to four minutes on one token"
Image from eBay
Here is information on a few of the games:
Tune-In - A music based game where players compose a melody by arranging musical phrases pre-programmed into the computer.
Mup-O-Matic - Players guess the Muppet character emerging in the video patterns. This was aimed at younger children.
Reflect - Players bounce a light beam off a mirror at angle to make objects on the screen react. One object was a rosebud which would blossom if hit with light.
Layer Cake - A variation of an ancient puzzle game where players move layers of cake to the correct sized plate.
Paddle Tennis - A tennis game that could be played with or without gravity.
Do you remember any others? Please let me know!