Yars' Revenge

In 'ultimate' mode, touching the left side of the screen activates the Zorlon Cannon. that change, I lost the ability to get the cannon up on the screen with the controller. But I found a game mechanic to bring it up instead. So the way you got the cannon to kill the monster was to eat some of the shield or touch the monster – because you could eviscerate the shield and if you had no way to get the cannon you

venetian blinds animation technique: an algorithm that horizontally reused and vertically interlaced sprites several times while rendering each frame, to give the illusion that the system had more than the maximum number of sprites allowed by the hardware.