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