Successfully fulfilling this whole list via co-op/online play will earn you almost 100%. Enjoy!
TEAM: SPYAthletics:*** Spoiler - click to reveal ***15x - Use RB to climb out of a window
10x - Climb up on plants (Can be found in Red Diamond near the blue terminal)
10x - Climb up a ladder
20x - Jump on a ledge and pull up
10x - Climb over a fence
20x - Use a zip line
15x - Use RB to slide under things or crawl in vents
20x - Perform a roll while standing
20x - Perform a roll while crouching
15x - Climb up a pipe
15x - Move hand over hand along a pipe
15x - Use RB to do escape ceiling move
15x - Use RB to do escape window move (Mash RB right before the window and you'll dive)
Stealth:*** Spoiler - click to reveal ***15x - Hack a complete file from a terminal and secure it without being seen
10x - Hack doors
_5x - Hack generators
20x - Switch Lights in rooms or halls (On or Off doesn't matter)
50x - Turn on night-vision
50x - Turn on thermal-vision
10x - Break neck from a upsilon soldier
20x - Hang on a catwalk and pull a upsilon soldier over the railing
20x - Drop down on a upsilon soldier head
20x - Secure a complete file, that contains data from all 4 terminals
Gadgets:*** Spoiler - click to reveal ***20x - Use injection
_5x - Use injection to heal a friend by standing near him
20x - Use smoke grenades
20x - Use flash grenades
10x - Use flash grenades and blind a upsilon soldier
20x - Use jammers
10x - Hacking a upsilon soldier
TEAM: UPSILONDirect Action:*** Spoiler - click to reveal ***50x - Kill a spy with your gun
15x - Kill a spy with a headshot
10x - Kill a spy with the gun or headshot holding a complete file
20x - Perform the charge attack (right bumper)
20x - Use the rotation attack (left stick)
10x - Use the rotation attack and hit a spy
10x - Grab and knock down a spy
Recon/Track:*** Spoiler - click to reveal ***50x - Use the flashlight
50x - Use the EMF
10x - Rope down from a railing
10x - Climb up a ladder
_5x - Repair a hacked generator
20x - Use zoom with gun
20x - Open doors
Gadgets:*** Spoiler - click to reveal ***20x - Use drones
_5x - Use drone and kill a spy
50x - Use grenades
20x - Use grenades and kill a spy
10x - Throw grenades with the aim line (Get line aim for holding for longer)
All credit goes to phiona at Xbox Achievements.
http://www.xboxachievements.com/forum/showthread.php?t=38567...Hope this helps :)