Editing Defender (1981 video game) (section)

=== Initial development ===
Space was a popular setting for video games at the time, and Jarvis felt the abstract setting would help obscure simple graphics that lacked realism.<ref name="Ultimate"/> Initially, Jarvis spent 3–4&nbsp;months developing color variations of [[Taito]]'s ''[[Space Invaders]]'' and [[Atari, Inc.]]'s ''[[Asteroids (video game)|Asteroids]]''.<ref name="Arc-Treasure-1">{{cite video game| title= [[Midway Arcade Treasures]]| developer= [[Backbone Entertainment|Digital Eclipse]]| publisher= [[Midway Games]]| date= 2003-11-18| platform= [[PlayStation 2]]| level= The Inside Story On Defender}}</ref> First inspired by ''Space Invaders'', he created a similar game with new gameplay mechanics. After spending a few weeks on the design, however, the team abandoned the idea, believing it lacked enjoyment. Development then shifted to emulating Atari's ''Asteroids'', but hardware differences between ''Asteroids'' and ''Defender''{{'}}s proposed specifications were problematic. ''Asteroids'' displays [[vector graphics]] on a special monitor, while the staff planned to use pixel graphics on a conventional monitor. The team experimented with recreating the game with pixel graphics, but also abandoned it because they felt the gameplay lacked enjoyment and visual appeal.<ref name="RG-55"/>

Believing their first attempts to be too derivative, the developers held brainstorming sessions. During a session, they agreed that one of ''Asteroids''{{'}}s favorable elements was its [[Wraparound (video games)|wraparound]].<ref name="RG-55"/> They felt a game that allowed the player to fly off the screen would be exciting and decided to create a game world larger than the screen displayed. The game's environment was made longer than the screen and scrolled horizontally.<ref name="Ultimate"/><ref name="RG-55"/> Expanding on the idea, they envisioned a version of ''Space Invaders'' rotated 90&nbsp;[[Degree (angle)|degrees]]. By changing the orientation of ''Space Invaders''{{'}} design, the ship moved up and down while flying horizontally. Large asteroids, an element from ''Asteroids'', were then added to the game world, but were later removed because the staff felt it lacked enjoyment.<ref name="RG-55"/> Jarvis intended the screen to scroll only from left to right; fellow Williams employee [[Steve Ritchie (pinball designer)|Steve Ritchie]], however, convinced him the game should be able to scroll in either direction.<ref name="Ultimate"/><ref name="RG-55"/>

After six months of development, the team felt the game had not made enough progress. They examined other games and concluded that survival was a necessary component to implement. To achieve this, they devised enemies to present a threat, the first of which was the "Lander".<ref name="RG-55"/> Jarvis enjoyed violent, action entertainment, and wanted the game to have those elements, but felt the action should have a reasonable objective. Inspired by the 1960s television show ''[[The Defenders (1961 TV series)|The Defenders]]'', Jarvis titled the game ''Defender'', reasoning that the title helped justify the violence.<ref name="Ultimate"/> He added astronauts to expand on the space theme and give players something to defend while they shot enemies.<ref name="Ultimate"/><ref name="RG-55"/> The element of flying over a planetscape was added after a brainstorming session between Jarvis and Ritchie.<ref name="Joystik1">{{cite journal| journal = JoyStik| title = Interview: Eugene Jarvis|date=September 1982| page = 7|issue = 1}}</ref> The landscape is depicted as a line only a pixel wide, primarily because the hardware was not powerful enough to generate anything more detailed.<ref name="RG-55"/>