On now.gg players can play the game on both PC or mobile on a web browser. Long downloads and annoying updates are over. Without downloading or installing the game, you can play your favorite Call of Duty Mobile in the cloud on your PC or mobile device.

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.

Call of Duty 4: Modern Warfare - Playstation 3.