I beat the single player mode about five minutes ago. What an incredibly fun, well put together title.
I don't play very many FPSes, by the way (last gen: Halo, Halo 2, Republic Commando, Star Wars Battlefront 2, Oddworld: Stranger's Wrath and Half Life 2 were the only ones I played). That might explain why I enjoyed Resistance as much as I did.