Here is the full list of all 19 The Hong Kong Massacre achievements.
10 000 enemies killed
Died 250 times
One hour in slowmotion
All challenges completed
Game completed
1000 enemies killed
Complete the first and second day without dying
Picked up 50 weapons
Complete first day without dying
All weapons and upgrades unlocked
Second day completed
25 Doors destroyed
First boss completed
100 enemies killed
Completed a level on first try
First weapon unlocked
Completed a level without slowmotion
First level completed
First enemy killed