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
Killed two Seraphs in one attack
Soared (Dash + jump) 100 times
Never hit off-beat in a Hell
Cleared a Hell using only Paz
Killed a Judge's Aspect with Terminus
Reached Hit Streak: 50
Killed 25 enemies while maintaining a Hit Streak
Destroyed the Red Judge
Completed all Torments
Died in a Chaos Crystal explosion
Destroyed the Red Judge aspect in Acheron
Reached Hit Streak: 35
Destroyed the Red Judge aspect in Nihil
Killed 8 enemies in 4 seconds
Killed 50 Behemoths
Achieved the top result in a Torment
Completed a Torment
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
Destroyed the Red Judge aspect in Stygia
Reached Hit Streak: 20
Destroyed the Red Judge aspect in Voke
Multi-killed 2 enemies
Reached Hit Streak: 10