"Gex" was created by Lyle Hall in 1993 shortly after he had joined Crystal Dynamics, and initially followed a movie stuntman named Gecko X before being retooled at the advisory of lead programmer Gregg Tavares. The game's lead character was intended as a mascot for the developer who could rival the likes of other immensely popular platformer characters – primarily Mario and Sonic the Hedgehog. Initially intended for completion in June 1994, and later in September of that year, development of the game took 21 months, with time constraints and a limited development team leading to numerous production difficulties. Several features were cut because of a necessity to complete the game on time, but some of these features were later re-added by a team of developers who programmed several other secret features into the game.