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