Atari issued this press release, announcing a 64-bit version of Shadow Ops: Red Mercury. The 64-bit version will be included with the 32-bit version when the PC port of the game ships next week. "The 64-bit version of the game [...] will allow for improved textures, better image quality, faster game performance and an enhanced gameplay experience." Though not explicitly mentioned in the press release, you'll need Windows XP 64-bit to run this.