"We're not ready to officially announce anything, but things are in the works. Look for the word in the coming month. We're going to ship with a full single player campaign and both offline and online multiplayer. We're also working with Nintendo now on getting LAN play working [via system link]." - Rob Nicholls, the game's designer.
Notice how he said Offline and Online AND ALSO LAN, meaning that the offline multiplayer is splitscreen. So far, the features confirmed are: 16+ Online Multiplayer, Voice Chat, Macthmaking, Customaizable : turning speed, cursor sensitivty, dead zone size, and running speed, Movable HUDS, 17 weapons +variants, 3 grenade types, LAN play, and splitscreen. Keep in mind that the game is still in it's early Alpha.