So I just started playing Resistance a week or two ago and finished it today (just in time for CoD4, which I also picked up today). Awesome game. It got a liiiitle repetitive at times since you were mostly fighting the same type of Chimera and sticking to the same two weapons (due to limited ammo for the fancier guns), but overall, a very impressive and fun title (even a year after it's release).
I was never much of a FPS fan, but all these quality games are really winning me over. Can't wait for Resistance 2 now.
So is it worth playing though a second time to check out the new weapons? The guy I borrowed it from is probably going to want it back sooner or later