Bringing its all-terrain jet hover bikes to space, 989 Studios planned a fourth entry to its Jet Moto series on the PS1 during the late 90s. Jet Moto 2124 had racers tearing across tracks set on Mars colonies and other futuristic settings with new features like slingshot grapples, trampolines and teleporters.

The game never made it to stores for a number of reasons including lackluster reviews/sales for Jet Moto 3, a new company president that didn't see the value in a fourth Jet Moto, and needed changes that required another 6 months of work. Thankfully, PlayStation Museum was able to gather some of Jet Moto 2124's developers for details on the project and a postmortem.

Along with offering insight on Jet Moto 2124 development process, design influences (e.g. Akira), and what went right/wrong with the project, PSM's article discusses contributions from Syd Mead, the famous industrial designer who worked on such film projects as Blade Runner, Aliens, and Tron. You can several pieces of concept art of the game's stages and bikes after the break.

PSM also posted a great Jet Moto 3 article with comments from 989 Studios's former president Kelly Flock and an interview with former programmer on the project (under developer Pacific Coast Power and Light) Ming Lee, the latter of which includes info on the game's engine and other technical details.