members who can be rescued to score additional points, but certain robots can either kill them or turn them into enemies. Destroying all vulnerable robots allows the player to progress to the next wave; the cycle continues until all lives are lost. Development Robotron: 2084 features monaural sound and raster graphics on a 19-inch CRT monitor. It uses a Motorola 6809 central processing unit that operates at 1MHz. Sounds are generated in software, with the same routines as in other Williams games of the era. The game uses a priority scheme to determine which sounds to play on a single channel. A custom blitter chip generates the on-screen objects and visual effects. It transfers memory faster than the CPU, allowing the game to simultaneously animate a large number of objects. The game was developed in six months by Eugene Jarvis and Larry DeMar, founders of Vid Kidz. Vid Kidz served as a consulting firm that designed games for Williams Electronics (part of WMS Industries), whom Jarvis and DeMar had previously worked for. The game was designed to provide excitement for players; Jarvis described the game as an "athletic experience" derived from a "physical element" in the two-joystick design. Robotron: 2084s gameplay is based on presenting the player with conflicting goals: avoid enemy attacks to survive, defeat enemies to progress, and save the family to earn points. It was first inspired by Stern Electronics' 1980 arcade game Berzerk and the Commodore PET computer game Chase. Berzerk is a shooting game in which a character traverses a maze to shoot robots, and Chase is a text-based game in which players move text characters into others. The initial concept involved a passive main character; the object was to get robots that chased the protagonist to collide with stationary, lethal obstacles. The game was deemed too boring compared to other action titles on the market and shooting was added to provide more excitement. The shooting elements drew inspiration from 1978 arcade game Space Invaders (1978), which had previously inspired Defender. The dual-joystick design was developed by Jarvis, and resulted from two experiences in Jarvis's life: an automobile accident and playing Berzerk. Prior to beginning development, Jarvis injured his right hand in an accident—his hand was still in a cast when he returned to work, which prevented him from using a traditional joystick with a button. While in rehabilitation, he thought of Berzerk. Though Jarvis