Full list of all 51 Aragami achievements. It takes around 15-20 hours to unlock all of the achievements in the base game on Windows.
The base game contains 39 achievements, and there is 1 DLC pack containing 12 achievements.
Destroy a Light Orb
Complete Chapter 3
Unlock a Skill
Complete Chapter 2
Find a Scroll
Obtain a 'Oni' medal
Perform 100 Shadow Leaps
Obtain a 'Kami' medal
Skip a cinematic
Complete Chapter 1
Obtain a ‘Yurei’ medal
Complete Chapter 4
Completer Chapter 5
Complete Chapter 6
Complete Chapter 7
Complete Chapter 8
Complete Chapter 9
Complete Chapter 10
Complete Chapter 11
Complete Chapter 12
Complete Chapter 13
Obtain all 'Yurei' medals
Obtain all 'Kami' medals
Obtain all 'Oni' medals
Find all Scrolls
Use 'Shinen' to swallow 3 guards at the same time
Get killed by an arrow while throwing a 'Kunai'
Perform an aerial kill from a 10m height
Concatenate multiple stealth kills
Perform your first Shadow Kill
Summon 100 shadows
Kill 100 enemies
Perform a Ledge Kill
Perform a Ceiling Kill
Die while performing a stealth kill
Die. Again. And again.
Unlock all Skills
Use an explosive light to kill a guard
Make a guard suspicious 3 times in a row
Complete Nightfall: Chapter I
Complete Nightfall: Chapter II
Complete Nightfall: Chapter III
Complete Nightfall: Chapter IV
Recover all Nisshoku Daggers
Kill two enemies at once with the help of Twin Shadow (Single Player)
Kill 4 or more enemies at once with the Explosive Kunai
Obtain all 'Kami' medals in 'Nightfall'
Obtain all 'Oni' medals in 'Nightfall'
Obtain all 'Yurei' medals in 'Nightfall'
Blind 4 or more enemies with a Shadow Grenade