Burns half as long. I have just finished the single player campaign. Explosive, thrilling, shocking, exciting but ultimately very, very short. Shorter than COD4 and more reliant on hectic set pieces that make it more about shooting what shoots at you, than accomplishing missions. That said, it is fantastic to look at, gorgeous visuals, stunning gameplay and fantastic AI. Infinity Ward have gone for a more cinematic feel, some very James Bond moments and more on rails vehicle sections than they have used in the past. This does have more of a, dare I say it, Treyarch feel to it. I just feel let down by being able to complete it in around 5 1/2 hours of play. OK I can go back and play through on Veteran difficulty and there are the added Specops challenges to get through as well. So thank God for multiplayer. Tomorrow I hit the Xbox live arena and will see if it's as much fun as COD 4. This only gets 4 stars because the single player campaign has let it down by being too short. COD4 was too short as well but rated 5 stars from me. A very, very good game but tainted by disappointment. Shame.
*************ADDENDUM********************************
OK I've had 2 days of play on multiplayer and I can see where IW have been focusing. I've only tried Free for All so far but I can tell you they've ballanced the maps, perks, weapons and add ons so brilliantly that they've leveled the playing field. On COD4 I was an average to slightly poor player, easily dominated by camping snipers and the 'pro' players. Now I most often rank 3rd or higher in the match scores! It just works so much better! And the whole perk and weapons system is just plain immense. I especially like the care package reward for 4 kills. With it you get a heli drop of anything from ammo, through air strikes, to AC130s and even a tactical nuke! You just have to stay alive to collect it before some other player nicks it! ( As a small note, I have seen some sniper players use care packages as bait, excellent idea!)
As good as the multiplayer is though, it cannot earn that extra star, sorry but the campaign just felt like a let down. Short, too hectic and a little too Hollywood rather than real world. Kinda like if Uwe Bolle directed a sequel to Platoon.