Resistance 2 is a lot of fun, both single-player and multiplayer (although the MP is obviously a lot more fun). Online co-op is fun for a while, until you realize it's the same thing over and over again, so I got bored of it towards the end of trying to get a class to level 30 (it sucks when you get a game of people who suck at their classes). The Competitive is a lot of fun, with Skirmish and probably TDM/DM being the most fun of the modes available (haven't tried the new mode yet). There are probably a lot of people still playing, with plenty coming back with the recently released map pack and the "patch" that introduced a new mode for Competitive.