Unlock Spec Ops Mode
Once you beat the game, you can choose "Campaign" and then "Free Mission" to select the newly available Spec Ops mode.
Tips and Tricks
Easy XP Gain
An easy way to gain quick XP to unlock guns and more abilities is to start out with Vector and gain his item vision passive ability. It will show you all the data in the world, pick them up and turn them into the laptops and you get 50 XP for each one, on top of this if you collect a certain ammount (usually 20) then at the end of the mission you get another XP bonus.
180 Degree Turn
Here's how to perform the 180 degree turn:
For PS3 version: L2 and Right Stick in any direction
For 360 version: LB and Right Stick in any direction
Acquiring Your Teammate's Firearm
Campaign mode - As long as you are playing on Veteran or Professional difficulty settings you can kill a teammate and take their firearm. Then simply revive them. When they respawn they respawn with a weapon. It is a really good trick if you are cornered in an area that has no ammo crates or boxes.
Bertha's First Aid Spray Trick
One of Bertha's perks is her ability to carry a first aid spray. Upgrade Bertha's abilities to include carrying a first aid spray on start up. Then, if you become injured and have no way to heal, Bertha is able to assist. As long as your playing on Veteran or Professional difficulty - kill Bertha, then revive her. When she respawns she will immediately administer first aid to you. You can do this as often as you like, making Bertha a valuable asset to your team.
Destroying Security Cameras For XP
In each level there are a number of security cameras. Since your mission is to destroy evidence, shoot out the security cameras to destroy them. Each camera destroyed gives you 50 XP. Destroy all the cameras in a level and you will acquire a 500 XP bonus for it. The cameras are encased in small black shiny domes.