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