A fun little electronic handheld football game released by Mattel in 1977. It's roughly the same size and colour as the original Game Boy and takes 1 9-volt battery.

The Computer's on Defence.
You control the Running Back.

Basically, you use the arrow keys to move the bright red blip from one side of the screen to the other, avoiding the dim red blips. You don't get to 'pass the ball' (you have no teammates), but you do have an option to punt or kick a field goal on the fourth down by pressing the K key.

Once I got the hang of the game it became pretty easy. It's a little tougher on PRO 2 than on PRO 1, though.