Here is the full list of all 28 Metal: Hellsinger achievements. It takes around 5-6 hours to unlock all of the achievements on Windows.
Died 20 times
Completed all Torments
Killed two Seraphs in one attack
Achieved the top result in a Torment
Completed a Torment
Never hit off-beat in a Hell
Killed a Judge's Aspect with Terminus
Died in a Chaos Crystal explosion
Reached Hit Streak: 50
Killed 25 enemies while maintaining a Hit Streak
Reached Hit Streak: 35
Cleared a Hell using only Paz
Killed 50 Behemoths
Destroyed the Red Judge
Destroyed the Red Judge aspect in Acheron
Destroyed the Red Judge aspect in Nihil
Destroyed the Red Judge aspect in Gehenna
Destroyed the Red Judge aspect in Incaustis
Got 666 kills (game total)
Obtained all weapons
Destroyed the Red Judge aspect in Yhelm
Soared (Dash + jump) 100 times
Destroyed the Red Judge aspect in Stygia
Killed 8 enemies in 4 seconds
Destroyed the Red Judge aspect in Voke
Reached Hit Streak: 20
Multi-killed 2 enemies
Reached Hit Streak: 10