- Laying prone lets you recover your breath faster but if any of them get the drop on you from any angle other than right in front of you, you're already dead. Sometimes, even them being in front of you won't save you.
- Don't sweat trying to get a headshot all of the time. If you need a dude dead like now, a gut shot is good enough. If it ends up incapacitating him instead, you can let him be because chances are someone's going to try picking him up and getting him back on his feet. They will actually get them up if you let them, so be careful of that. No, you don't get bonus points for shooting them while they're down, if score is your main concern at all.
- Always be moving and try to avoid shooting from the same spot twice unless you've got your flanks well-covered or you're so far away that they can't do anything about it to begin with. The AI is really good at surrounding you and you don't carry that much ammo for your other guns if/once things go tits up. On normal and under, you leave behind an image of where the enemies last spotted/became aware of you. You can take advantage of this and set up some traps for anyone who ends up searching for you up there.
- Once you place down a mine, you're set with it until it goes off. It'll never go off under your feet (thank god) but you're not getting it back, either. You can cancel using the trip-wire if you don't like the initial stake being where it's at. Once you put down the charge, though, you can't pick it back up again.
- Finally, just take it nice and slow with some of your shots because you will be dealing with moving targets at times and focus time isn't going to help you if you go crazy with the aiming anyway.