First of all, the campain in this game lasts around 6 hours, which is far too short. While it lasts its a blast, however the story is ridiculously OTT and not very well explained. You will often be playing a mission and be wondering - why am I here/what am I doing? If you were to review the single player alone it would only be a 3/4 star game.
However, the single player is only a third of the game, and with the spec ops and online play, there is much more to see. These modes are excellent and give the game endless lasting appeal.
Online multiplayer is unbelievably addictive, tonnes of rewards, unlockables, etc, it will take over your life!!! Weapons and maps are far improved over COD4 and there is far less camping going on.
The multiplayer on this is worth the asking price alone, but I hope infinity ward do not neglect the plot and duration of the campaign mode again in the sequel...