E-102 γ is somewhat a staple in the Sonic series, being the first robot to be fully playable platform-wise and even exhibit a story. With his whole life depicted on screen, he is arguably one of the most developed characters in the series.
Only two pieces of concept art have been found of Gamma, shown on various Sonic fan sites. His most obvious basis is the EggRobo from the earlier games, though he also bears resemblance to many renowned battle robots in science fiction, particularly ED-209, a law enforcement droid from the RoboCop series, most obvious due to its "chicken walker" design.
It is believed many fans asked for this shooting ability, but Sega and Sonic Team felt that Sonic the Hedgehog using a gun was inappropriate. The developers thus decided to make another character with this ability in lieu of giving Sonic a gun. In Sonic Adventure 2, this gameplay style was adopted for Dr. Eggman and Miles "Tails" Prower's mechanized walkers. However, in a recent GameSpot interview, a developer assessed Gamma's creation as simply because "Kids like robots".
