I think my favorite part of the game is single player. This is because you can play it however you like. You can go in an plow them down with the shotgun or hide in bushes picking them off one at a time. I have beaten it twice on normal, once on hard, and now working on Delta. It just dosent get old.
BTW, which style do you guys play? Loud or stealthy? Myself, I like to sneak in and kill them one at a time without setting off alarms. That means 6 men, 6 bullets.
-dan