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