Here is how I feel. It was awful and did not live up to RFOM which was by far the superior game. In fact, rather then re-listing all the bull I didn't like, I'll just copy paste a quote of mine from another thread.
"I played Resistance 2 (as well as Resistance: Fall of Man. I may make references to RFOM due to the fact that I liked the first one a lot more) and beat R2 on Difficult and SuperHuman (the hard difficulty, and the hardest difficulty, respectively). Personally, I found the game's campaign mode to be easy, but I'm not criticizing you as a gamer, that's way they put in place different difficulties, so one may challenge themselves at their own playing level. If it matters to anyone that much, it took me 9 hours on difficult, and 7 hours on superhuman.
I actually found the story-line to be fairly well put together. (I have never played GoW, but I hear story line wise they are similar.) However, I thought the guns were intuitive (most were from RFOM. come on, there is a gun that shoots saw blades, it may be the worst gun in the game, but the very concept it awesome), and I thought for the most part the gameplay was decent for the single player. Yes, crouching was a pain in the ass, but at the same time, it took more than three shots to take one down.
Considering you have not played R2 multiplayer, I will say that personally I thought it was a disgrace to the first game. The first game did not give into the two weapon approach that EVERY game in the last decade has started to do because of Halo's success. But yeah, the Co-op is repetitive, and quite boring after the first few times.
And well the competitive multiplayer is awful, in my opinion. Absolutely awful. The maps are exact clones of the co-op, and sometimes there is a map that has been modified off the single player. Virtually every map gives an unfair advantage to one side. Each player can select a berserk (i.e. CoD4 Perks on steroids) which for one example, Ironheart reduces the amount of damage one takes by half (similar to Juggernaught from CoD4) and is unfortunately one of the most overused and unbalancing berserks in the multiplayer (and to clarify for those who have not experienced the online, you cannot always have the berserk activated like in CoD4, they must be achieved by gaining a certain amount of XP). However, the number one offense Insomniac did was offer a ridiculous amount of one-hit kills. By my count, there are 6 different options for a one-hit kill (I counted the laark and pulse cannon twice due to the fact that they both offer two different attacks for different variations of one-hit kills). And the 40mm for the Carbine is distributed like candy on halloween. After every kill, the "killer" (or whomever may run over the ammo drop) has a 1/3 chance of getting a 40mm. So even decent players suffer unnecessary kills in an unbalanced online system.
But to digress, the online is just unfortunate (I could continue ranting about it, but quite frankly no one would care, and I suppose if you're still reading you've gotten the idea that I don't personally enjoy it). And please don't revert to the 'you must suck at the game" argument. I have beaten the single player on superhuman, as aforementioned, I have beaten the Co-op, and I have a 2.2 K/D on the multiplayer (I'm not saying I'm great, I'm saying I'm better than most).
But to summarize, the point I'm trying to get at is, if you (General Rogue, or anyone else who agrees with him) thinks that the single player was bad, the online is much worse, and while I may disagree with you about the single player, I must agree that the game is garbage, and certainly did not deserve a decent review."
That was directed at someone who had not played the multiplayer, but yeah, I prefer the first game.