Before Far Cry and Crysis, developer Crytek worked on a sci-fi FPS game by the name of Engalus, which its lead designer describes as "Half-Life meets Metal Gear Solid in an intense story driven action/adventure game like none other on the PC."
A recently discovered online portfolio of Engalus lead designer and former Crytek employee Brian J. Audette contains screenshots, a 40+ page script, a design document, a dead link to a demo, and links to a Deux Ex mod that recreates the experience that Engalus was to give.
Engalus was in production for 5+ months and was even privately shown at E3 in 2000. The game had an ambitious script, its own engine that rivaled Quake 3, and the team that would go on to create Far Cry. So, what went wrong? The lead designer felt he was over his head and left for a smaller role at Turbine (read more here). I bet he kicks himself over that decision, these days.