PERFECT DARK ZERO TIPS & TRICKS
Allies Squad Tactics
Unfortunately you'll find yourself in situations from time to time where you're fighting alongside and escorting a few allies. You will find these allies won't be very smart, and will often get themselves killed despite your noblest efforts. They will walk directly into enemy fire and fail to retreat to safety once they start getting shot. This will sometimes cause you to fail your mission.
Easy weapons
When one player has gotten a weapon that another desires, go to Club: Stakeout on Agent mode. Drop that player's weapon to a second player. Have any one of those players continue through the level normally. If done correctly, the new player can have the weapons in less than three minutes. The faster way through the level is to run in the club after the first objective is complete unarmed, and rush to the very top to Jack Dark.
Weapon locations
Remember that the first and last level do not count for getting weapons. To get a weapon to keep for later use, keep it in your inventory at the end of the level. This is also useful with the "Easy Weapons" trick.
Datacore: Demolition - weapon location
P9P (pistol): you start with this gun.
Nightclub: Stakeout - weapon locations
DEF-12 shotgun (close combat): find on the enforcer in the beginning (after you scan him). Falcon (pistol): found on almost any guards, such as the first two. UGL Liberator (SMG): Found on the guard on the third floor. He should have two of them.
Subway: Retrieval - weapon locations
CMP-150 (SMG): found on some guards. DW-P5 (SMG): found in the only open storage crate after you have gone through the parking garage.
Rooftops: Escape - weapon locations
Jackal (Heavy): found on the sniper if you did not shoot it off the building. The easiest way is to put away any weapon you have (Up) and use disarm (RB). M60 (Heavy): found once you get to the fire doors. Go past the fire doors and lock pick the door. It should be standing atop an artillery box next to the guard.
Mansion: Infiltration - weapon locations
Magsec 4 (Pistol): found on all guards at the beginning of the level. Viblade (Close Combat): found once you get in the mansion. It is standing on a pedestal in the middle of the laser maze.
Laboratory: Rescue - weapon locations
KSI-74 (Assault): found on almost all blue guards. Magnum (Pistol): found on the yellow suited guards that come once the alarm is triggered.
River: Extraction - weapon location
Rocket Launcher (Heavy): it is recommended to get this weapon when in Co-Op mode, as it is quite difficult to get. Once you get outside, open the gate and kill the guards. On the hovercraft that you take, press Y when by the gunner to switch for another heavy weapon (M60 and Plasma Rifle only).