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