Playing the first game is funny cause it was pre-Modern Warfare, the controls seem so bizarre.
Awesome game though, my favorite is the first and Retribution on the PSP.
Resistance 2 coop was so damn good. That was back when the PS3 was still struggling a bit and that Resistance 2 coop was so much fun, it wasn't anywhere near as "good" as L4D but all the same, it gave PS3 gamers something fun to coop on.
Series never found it's footing but they're all solid games, it's the narrative that wrecked it all. One of the reasons I liked Retribution so much, best story out of all the games.