Here is the full list of all 53 Killzone: Mercenary trophies - there are 42 bronze, 8 silver, 2 gold and 1 platinum.
Collect all trophies
Kill 10,000 enemies
Access the Security Center without triggering the alarm in 'Justice For All'
Earn 1,000,000 Vektan dollars
Complete 100 Multiplayer game rounds
Rescue an injured teammate in Multiplayer
Shoot down 10 enemy VAN-Guard drones in Multiplayer
Kill an enemy at long range
Complete all mission contracts on Veteran difficulty
Collect a full deck of Valor cards
Complete all Covert, Demolition and Precision contracts
Complete all Precision contracts
In 'Exit Wounds', successfully melee Benoit from behind.
Collect all intel items
Complete all Demolition contracts
Complete all Covert contracts
Burn an enemy in the Lab 01 incinerator in 'Blood Money'
Lock the Admiral in the Vault and detonate the demolition charges in 'Blood Money'
Ensure Dr Savic. dies in 'Hostile Takeover'
Achieve 1000 headshots
Destroy the Helghast extraction dropship in 'Lights Out'
Destroy all barnacles in 'The Package'
Use every weapon, grenade, armor and VAN-Guard available in Blackjack's armory
Win at least one round of all Multiplayer modes
Buy everything in Blackjack's armory
Get crushed by an incoming VAN-Guard capsule
Attain an ace Valor card ranking
Kill all troops before they rappel out of a dropship
Destroy the Helghast Tank without using a D-Charge in 'Justice For All'
Interrogate the Captain in the Judge's chamber and save his hostage in 'Justice For All'
Complete all mission contracts
Complete mission contract 'Blood Money'
Brutal melee an enemy from behind while using the Ghost VAN-Guard
Complete mission contract 'Hostile Takeover'
Ensure Dr. Savic lives in 'Hostile Takeover'
Collect the contents from 10 VAN-Guard capsules in Multiplayer
Achieve a 10 kill streak in Multiplayer
Complete mission contract 'Lights Out'
Recover after being tranquilised by an enemy in Multiplayer
Complete a Multiplayer game round
Kill an enemy while they are interrogating a teammate in Multiplayer
Perform a Brutal Melee counter gesture in Multiplayer
Complete mission contract 'The Package'
Complete 'The Package' without any civillian casualties
Interrogate an enemy
Complete mission contract 'Diplomatic Incident'
Brutal Melee 12 enemies consecutively
Complete mission contract 'Lightning Strike'
Complete mission contract 'Code Of Engagement'
Make a purchase in Blackjack's armory
Complete mission contract 'Justice For All'
Complete a VAN-Guard hack, making no mistakes
Visit Blackjack's Armory during a mission