It doesn't bring anything new to the franchise but 32 multiplayer online on the wii is one reason to buy.
The story mode albeit hard is very samey. all the maps feature you killing hordes of enemies to get to one place and then to another etc. the ai aren't that bright, but if you have the difficulty on high then you can expect to die quite easily if you understimate them. Apart from that the story isn't anything brilliant and really will feel quite stale and you'll maybe even regret going through it.
Although the one player campaign may be nothing to go by, the 32 player online multiplayer matches are something to behold. Joining halfway through a mssive struggle of capture the falg is excellant and you'll soon find yourself completely owned if your not great at the game. that may sound bad but you can play against other newbies and constantl going against better players will have you learning new tricks and you'll gradually get to their level anyways.
Thats pretty much it from this game, except an arcade mode that i suppose is aimed at the younger audience to ease them into the game, but for any hardcore fans its nothing special and can be disregarded as a waste of disc usage.
in conclcusion the games one player campaign isn't great, but it can be fun depedning on what your looking for. but this games real gem is the online multipayer. you get some great matches and the fact you can play with 32 other players online is a great leap forward for the wii's dismal online cpabilities. So really if you've got online and your looking for a good FPS game then this is it, but if you haven't got online and your looking for a great shooter, then look elsewhere. and even though I've given the game a relativly high score, its only because of the online and how great it is.