Am I watching a movie?
Though the single player was amazing enough, NaughtyDog was nice enough to give us multiplayer. Online has everything that you will come to love about the single player, platforming, stealth kills, cover, and best of all propane tanks >=). Leveling up is a blast! Though the booster idea may be a rip off from cod, uncharted prooves that they can take a great idea and keep it great. The leveling up system is based on the amount of money you accumulate. However, once you hit level 40 youll find that it takes alot of time and effort to level up.
Ok, I know what your thinking "Wow, amazing single player and multiplayer! How could it get any better!?" Well... NaughtDog asked themselves that same question so they added COOP! Co-op comes in three different forms objectives, which is basicly the campaign with friends. Survival, my personal favorite, where you fight wave after wave of enemies with three friends. Gold rush, easily the most hecktic of the three, in gold rush you need to carry treasure from one side of the map to the other...basiclly ctf with ALOT of A.I. coming at you and your team.
Overall, Uncharted 2 is an amazing game that will keep you busy for dozens of hours, entertain you and anyone lucky enough to watch you play, and has very few and very minor flaws.