It's kind of interesting how Red Orchestra 2 and Rising Storm are the multiplayer games that I do the best at. When I play Call of Duty or Battlefield 3 or all the other "easy" games with a fanbase heavily populated by kids, I tend to stay at the bottom of the ranks; the other guys almost seem to be operating reflexively. Even on hardcore, I barely do any better.
And then in a realistic shooter where one good shot will kill you and nearby bullet and explosion impacts makes it almost impossible to fight back, I consistently get on at least the upper half of the scoreboard. I once made a dozen kills in less than 5 minutes with a submachine gun at the very beginning of a match on Peleliu. On Black Ops, I'd probably have made one kill per minute.
