Great game, but could have been better
I thought "Resistance 2" was a pretty good game, especially what it was doing with its XP system. Rather than keeping all aspects of the game separate, "Resistance 2" combined single-player, 8-person co-op and multiplayer XP (and, thus, your rank in the game) into a single number. This allowed people that only liked one or two modes of the game to only play those and not be punished. I wish more games would do it that way.
While I enjoyed the single-player mode of the game, I really, really liked co-op. 8-player co-op, when you get a good group together, is amongst the best experiences on the PS3. You have your choice of three player classes that must work together to get through each level. To improve replayability, Insomniac basically added a "shuffle" feature to each co-op level, having you start at different points on the map each time you played that level, giving you a different experience each time.
I also very much enjoyed the Skirmish mode of multiplayer, that basically pitted two teams against each other, but with random objectives, including capture points and assassinations. You wouldn't know what the next objective would be, allowing for great replayability. The mode was always "fresh," never stale.
I wish Insomniac had supported the game better later in its release, however. They added one DLC mappack which really only added small capture-the-flag levels to the multiplayer experience, as well as a few extra skins (some free, some for purchase). While I applaud the effort, I would have preferred new Skirmish maps or more co-op levels.
"Resistance 2" is a great shooter for the PS3, but at this point, there aren't many playing it anymore. Hopefully, once it's released as a "Greatest Hits" title, more people will hop on and give it a try. It's worth it for the co-op alone.