Editing Robotron: 2084 (section)

=== Enemy designs ===
Each enemy was designed to exhibit a unique behavior toward the character; random elements were programmed into the enemies' behaviors to make the game more interesting.<ref name="Halcyon"/><ref name="gamesTM-36"/> The first two designed were the simplest: Electrodes and Grunts. Electrodes are stationary objects that are lethal to the in-game characters, and Grunts are simple robots that chase the protagonist by plotting the shortest path to him.<ref name="Halcyon"/><ref name="Retro60"/> Grunts were designed to overwhelm the player with large groups.<ref name="gamesTM-36"/> While testing the game with the new control system and the two enemies, Jarvis and DeMar were impressed by the gameplay's excitement and fun. As a result, they began steadily increasing the number of on-screen enemies to over a hundred to see if more enemies would generate more enjoyment.<ref name="Halcyon"/><ref name="Retro60"/>

Other enemies were created to add more variety. Large, indestructible Hulks, inspired by an enemy in ''Berzerk'', were added to kill the humans on the stage. Though they cannot be destroyed, the developers decided to have the protagonist's projectiles slow the Hulk's movement as a way to help the player. Levitating Enforcers were added as enemies that could shoot back at the main character; Jarvis and DeMar liked the idea of a floating robot and felt it would be easier to animate. A projectile [[algorithm]] was devised for Enforcers to simulate enemy [[artificial intelligence in video games|artificial intelligence]]. The developers felt a simple algorithm of shooting directly at the protagonist would be ineffective because the character's constant motion would always result in a miss. Random elements were added to make the projectile more unpredictable; the Enforcer aims at a random location in a ten-[[pixel]] radius around the character, and random acceleration curves the [[trajectory]]. To further differentiate Enforcers, Jarvis devised the Spheroid enemy as a robot that continually generated Enforcers, rather than have them already on the screen like other enemies. Brains were conceived as robots that could capture humans and brainwash them into enemies called Progs, and also launch cruise missiles that chase the player in a random zigzag pattern, making them difficult to shoot down. DeMar devised the final enemies as a way to further increase the game's difficulty; Tanks that fire projectiles which bounce around the screen, and Quarks as a tank-producing robot.<ref name="Retro60"/>

In the summer of 2012, Eugene Jarvis wrote a comprehensive evaluation of the Robotron Enemy Dynamics: the game is [[hard-coded]] with 40 waves, whereupon the game repeats wave 21 to 40 over and over until the game restarts back to the original wave 1, once the player completes wave 255. In the same year, Larry DeMar provided details on how to trigger the secret copyright message in ''Robotron''.<ref>{{cite web | url = https://www.youtube.com/watch?v=4UJd2iFuTfY | title = Larry DeMar shows Robotron secret | website = [[YouTube]] | access-date = 2015-08-18 | archive-date = 2015-11-26 | archive-url = https://web.archive.org/web/20151126080839/https://www.youtube.com/watch?v=4UJd2iFuTfY | url-status = dead}}</ref>