Successfully complete one of the following tasks to get a trophy:

Big Spender (Bronze): Spent more than 10000 SaberSense chips at kiosks.
Tooled-Up Agent (Bronze): Purchased all new weapons and weapon upgrades (excluding ammo capacity).
Combat Trainee (Bronze): 100 enemies defeated.
Combat Expert (Bronze): 500 enemies defeated.
Plasma Gun Expert (Bronze): Defeated 100 enemies with Plasma Gun.
Cluster Rifle Expert (Bronze): Defeated 100 enemies with Cluster Rifle.
Flame Thrower Expert (Bronze): Defeated 100 enemies with Flame Thrower.
Freeze Gun Expert (Bronze): Defeated 100 enemies frozen by the Freeze Gun.
Shot Bolter Expert (Bronze): Defeated 100 enemies with Shot Bolter.
Incendiary Charge Grenadier (Bronze): Defeated 50 enemies with Incendiary Charges.
RDV Pulse Cannon Expert (Bronze): Defeated 50 enemies with RDV Pulse Cannon.
RDV Homing Missile Expert (Bronze): Defeated 50 enemies with RDV Homing Missiles.
NanoHack Expert (Bronze): Defeated 50 enemies using NanoHacked enemies.
Silver Data Disk Discoverer (Silver): Collected 50% (25) of all Silver Data Disks in the game.
Wealthy Agent (Silver): Accumulate more than 5000 SaberSense chips.
Master Agent (Silver): Fully upgraded character with all possible weapons and upgrades.
Combat Veteran (Silver): 1000 enemies defeated.
Sharp Shooter (Silver): Achieved an average hit rate of at least 80% with projectile weapons.
Marching Agent (Silver): Walk more than 20km with Darwin.
G-Force Wings (Silver): Fly more than 2km with Mooch.
Intelligence Expert (Silver): Scan 100 items in the game.
G-Force Trainee (Silver): Completed game on Easy difficulty setting.
G-Force Recruit (Silver): Completed game on Normal difficulty setting.
G-Force Agent (Silver): Completed game on Challenging difficulty setting.
Distinguished Service Medal (Gold): Completed game twice.
G-Force Rapid Response Agent (Gold): Completed game in under 8 hours (on any difficulty setting).
Silver Data Disk Expert (Gold): Collected 100% (50) of all Silver Data Disks in the game.
100% Complete! (Platinum): You have unlocked every other trophy.

Additionally, there are sixteen secret trophies:

Mission Accomplished: "Snowball Unleashed" (Bronze): Finish mission.
Mission Accomplished: "Countdown" (Bronze): Finish mission.
Mission Accomplished: "Saberling Offices" (Bronze): Finish mission.
Mission Accomplished: "Central Computer" (Bronze): Finish mission.
Mission Accomplished: "RDV Retreat" (Bronze): Finish mission.
Mission Accomplished: "Distribution Center" (Bronze): Finish mission.
Mission Accomplished: "Assembly Lines" (Bronze): Finish mission.
Mission Accomplished: "Chip Manufacture" (Bronze): Finish mission.
Mission Accomplished: "Reactor" (Bronze): Finish mission.
Mission Accomplished: "RDV Escape" (Bronze): Finish mission.
Mission Accomplished: "FBI Infiltration" (Bronze): Finish mission.
Mission Accomplished: "Locate the Real Saber" (Bronze): Finish mission.
Mission Accomplished: "Rescue Saber" (Bronze): Finish mission.
Mission Accomplished: "Clusterstorm" (Bronze): Finish mission.
Mission Accomplished: "Satellite Menace" (Bronze): Finish mission.
G-Force Special Agent (Silver): Completed game on Special Agent difficulty setting.