One of the best games for wii so far.
But the real fun lies in the online play. You start as a level 1 and can only enter boot camp mode. By killing other players, assisting in kills and getting match bonuses you earn experience (XP). The experience adds up and eventually you level up. By levelling up you can unlock different weapons, perks, and game modes. If you get a certain amount of kills or head shots with a weapon you earn XP bonuses and even attachments for that weapon. Also once you reach level 65 you get the chance to enter prestige mode. Prestige mode resets nearly everything but you get a funky looking badge and an extra custom class slot. You can go through prestige mode up to ten times each time earning you a new badge.
I recommend that anyone who owns a wii should buy this game and if you have it connected to wi-fi then there's even more reason to buy it.