There are 29 Trophies that can be collected.

BRONZE

1st Mission Complete
You completed the first mission on any level

Silent Assassin
A Silent Assassin rating has been awarded

Normal Mode Complete
Completed normal difficulty

All Melee Weapons found
You have found all Melee Weapons

All Hand Guns collected
All Hand Guns collected and displayed in the training room

All Machine Guns collected
All Machine Guns collected and displayed in the training room

All Assault Rifles collected
All Assault Rifles collected and displayed in the training room

All Shotguns collected
All Shotguns collected and displayed in the training room

All Sniper Rifles collected
All Sniper Rifles collected and displayed in the training room

All Heavy Weapons collected
All Heavy Weapons collected and displayed in the training room

1st Kill
A successful kill has been performed

Killed the wrong guy
An innocent person has been killed

SILVER

5 Normal Silent Assassins
5 Silent Assassin ratings awarded on the Normal difficulty

5 Expert Silent Assassins
5 Silent Assassin ratings awarded on the Expert difficulty

Expert Mode Complete
Completed expert difficulty

Headshot
A successful headshot has been performed

Sleep well
You knocked a victim out

Poisonous
You poisoned a victim

Firey Fire
You used explosives on a victim

GOLD

5 Professional Silent Assassins
5 Silent Assassin ratings awarded on the Professional difficulty

Professional Mode Complete
Completed professional difficulty

All Firearms collected
All Firearms collected and displayed in the training room

47 kills in a mission
A mission has been completed with precisely 47 kills

PLATINUM

Perfect Assassin
Unlock all trophies

5 SECRET

http://www.ps3trophies.org/game/hitman-contracts-hd/trophies/