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