Although I´m more a singleplayer type of gamer I even loved the multiplayer demo, yeah right, I even played the demo for hours and oh boy was that fun using the grenade launcher after obtaining an upgrade point with the possibility to let it remotely explode with the press of the mouse button. Also the other weapons like the let u shoot like an electricity ball that dealt out area damage, a when upgraded fast loading shootgun an rocket launcher with a homing in missles similar to that in CoD4 to destroy tanks or like in Ace Combat. But skill won in the end. The vehicles had kind of bad controls like in Halo but were neat on some occasions.
You know it is the same guys that really developed Unreal Tournament, namely Digital Extremes when you played that multiplayer. The campaign wasn´t that memorable but ok. If you make the multiplayer playable again with the map editor I never tried then I´d hopp on board.
Sadly only the Xbox version had a coop-mode for the campaign.