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