Yet another project by Wally, just a little bit older than the previous one, is Denial ’77. The game is loosely modelled on Space Zap, an arcade game from 1980.

You’re protecting the base in the centre, move the joystick in the direction you want to fire. The base heats up when you fire, changing colour and expanding. The base firing rate slows as the base heats up. The base also heats up when hit. It’s game over if the base hit when it is overheated. The level number is the only scoring mechanism.

http://wallysfolly.blogspot.co.at/2016/09/atari-2600-denial-77-release-notes.html