Here is the full list of all 20 The Hong Kong Massacre trophies - there are 5 bronze, 6 silver, 8 gold and 1 platinum.
All trophies unlocked
First enemy killed
First level completed
First Boss completed
First weapon unlocked
25 Doors destroyed
100 enemies killed
250 deaths
Second day completed
1000 enemies killed
One hour in slowmotion
Picked up 50 weapons
Completed a level on first try
Completed a level without slowmotion
Complete first day without dying on normal difficulty
10 000 enemeis killed
Complete the first and second day without dying on normal difficulty
All challenges completed on normal difficulty
All weapons and upgrades unlocked on normal difficulty
Game completed on normal difficulty