The Lockwood 300 shotgun in Call of Duty: Modern Warfare 2 has been nerfed in the latest patch, reducing its damage range with the Maelstrom Dual Trigger attachment.
The Lockwood 680 is straightforward and powerful at the right ranges, but that range is quite short compared to the likes of the similar-feeling Bryson 800.
Playable in both 3D and non-3D on the Xbox 360, PlayStation 3 and PC. Call of Duty: Black Ops for Windows PC is NVIDIA(R) 3D Vision(R)-Ready and supports stereoscopic 3D gaming using 3D Vision active-shutter glasses and NVIDIA GeForce GPUs.
Yes, all of the Call of Duty: Modern Warfare games on PS3 have a singleplayer campaign. Some of the campaign modes have a co-op mode, but I'm not sure which of the games has this. Call of Duty 4: Modern Warfare has singleplayer and multiplayer.