- The key to strategic team based shooters is simple... it's the Seven P's! Proper Preparation and Planning Prevents Piss Poor Performance. The number one mistake you can make is to rush into any room without a plan or a strategy. For the vast majority of the games, time is on your side, so use it.
- Most the weapons are very well rounded. In my experience, though, I would always keep at least one Assault Rifle, and then whatever else you want to play with (depending on your play style). Don't take a Sniper Rifle, however, because you can do the same damn thing with an assault rifle and a good scope, AND you don't need to dedicate a weapons slot to it.
- The 6x scope is your friend.
- Play with a friend. More fun!
- The machine guns typically have enough ammo to do the level twice over. They are accurate enough for killing foes with single shots or burst fire, and useful for hosing down an area with lead to keep dem terrists hiding behind things.
- the SCAR CQC with a silencer and hunting scope is an amazing sniper and multipurpose weapon.
- Don't carry breaching charges, your NPCs have them, and you would be better served with frags, fire, flash, or smoke grenades.
- Smoke grenades are mission savers. throwing one at a downed partner will give you cover to revive them when running out there naked would get you swiss cheesed.
- In this game you gain weapon experience playing any mode; play co-op terrorist hunt with a buddy, split-screen, for shits and find out you unlocked the best sniper a few hours in.
- I don't believe this works in multiplayer but in singleplayer a sniper, blind-fired, is 100% accurate and will hit exactly where the invisible crosshair is pointed. Congratulations, you are now the proud owner of a sniper and a shotgun.
- The best loadout is two machineguns (as in, the heavy, belt-fed ones, preferably the HK21 and whatever other one you like), a Glock 18 and the heaviest armour you can get.
- Put the recoil manager stock on the HK, and put a scope on the other one. Extended mag on the G18. All you need to do is point at where a guy might be, shoot until you gain some exp, then repeat with another dude.
- On Realistic, assault rifles are a must for any close quarters combat, but they're not as good for sniping, since they lack enough punch. This is pretty much the only time to use the sniper rifles.
- If you find you have the wrong loadout for a segment, and it's causing you to die (i.e. Machine gun and SMG in an area with a lot of long range combat), quit to the main menu, and change your loadout there. This has helped me a bunch on my latest run.
- Don't rush in, always take cover. If you rush in, you will die. if you take cover, most of the time you'll be fine. Grenades from cover and blindfire with an MG are a great way to clear a room.
- Breaching Charges will kill anyone behind the door you blow open. This comes in handy in a couple places.
- Pistols should always get a high-cap mag. Laser sights are generally worthless, and if you're using your pistol, you're likely out of ammo for everything else, and those extra few shots can help a lot.
- If you use a camera to get a picture of your face, it WILL look like a horrifying creature or burn victim. Unfortunately this does not seem to affect enemies.
- Shields suck, but if you must use one, crouch. You cover your legs and are less likely to get shot.
- Enemies with shields suck. Shoot for the legs or their gun arm. If they're reloading, light them up. Grenades also seem to help.
- Your allies are a godsend if you are stuck. when all else fails, leapfrog through an area.
- Don't rush. The only times you need to act quickly is if there are hostages that you have seen. Until you see the room the hostages are in, the AI will just stand there and not care. There is always dialog between the enemies, or the enemies and the hostages. Use this to flash+clear the room and you're golden.