The game's antagonist General RAAM was a last-minute addition to the game, and due to time constraints and looming production deadlines, his backstory and related context in Act 5 were not included in the original Xbox 360 release of Gears of War, but would be included in all of its future releases.

RAAM was also named after the owner of a local Indian restaurant that Epic Games' staff frequented during development.
Contributed by MehDeletingLater
The Locusts were originally going to be called "Geist". Epic had a hard time shipping this, however, because Nintendo previously had a game using the same name.
Contributed by ShyanVixen
Gears of War was originally going to be a game called 'Unreal Warfare'. It was going to be a large multiplayer game that was set within the Unreal universe and would be the next Unreal game after Epic's previous Unreal Tournament. However, the team decided to strike the game from the Unreal series because it travelled too far from the Unreal universe.
Contributed by ShyanVixen