I bought this game for nestalgia and it was everything I wanted and more.
I haven't yet finished the single player game, but so far the online play is just too much fun to waste time with the single player... I guess I can finish it if I ever get bored of the online play.
Only reason it didn't get a 10 from me was that none of the original maps where included and you don't have weapon caches or armor lying around in the multiplayer. The multiplayer goes off of a experience earns you weapons and gadgets/attachments, with which you can create your own load out for your level character. I like this system because it makes you want to continue competing to unlock more rewards. But, I do wish there was a mode letting you play with the original feel with the armor and weapon caches.