I borrowed a PS3 so I could beat this game, and I beat it twice (second time on TB Extreme). I definately used the M82A2 for almost everything on my second runthrough, except the railgun for gekkos and occasionally the grenade launcher. I enjoyed the gameplay (camo is actually useful!) but the plot was lacking. The cutscenes were kind of intrusive too... there's really only about 30-40 minutes of actual gameplay in Act 5. Oh well, still a good game.