HIDE THE WEAPONS
Press at the same time:
+ 
+ Press 
+ 
+ 
ADVANCED HUD
This viewing mode will allow you to see the coordinates of key points on the screen:
You must press at the same time:
+ + Press + + 
UNLOCK PAN-CAM (panoramic camera)
Run the advanced Hud trick and when activated, press and hold:
+ 
+ 
HUNT AN ANTI-AIRCRAFT WRIGHT
In the first mission you can find one. Get close to him and get on with instead of pressing as usual.
If you look at the lid, you'll see that you can see Wright's head. Now you can shoot it with the rifle (hold to enhance the shot) and the Wright will be yours.
CONVERT A TURRET INTO A SUBMGISON
With two SMGs in your possession, use a turret and hold +
By doing this, you will create the ultimate weapon by embedding the SMGs into the turrets.