Here is the full list of all 50 Wolfenstein: The New Order achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Collect all letters
Collect all gold items
Solve the fourth Enigma code
Solve the third Enigma code
Solve the second Enigma code
Solve the first Enigma code
Unlock demolition perk 5
Unlock demolition perk 4
Unlock assault perk 5
Unlock tactical perk 7
Unlock tactical perk 6
Unlock demolition perk 7
Unlock demolition perk 6
Choose to save Fergus
Complete game on any difficulty
Complete game on I AM DEATH INCARNATE! (or ÜBER)
Complete game on ÜBER
Collect 25 gold items
Release friend
Unlock demolition perk 8
Unlock tactical perk 5
Defeat the London Monitor
Unlock assault perk 7
Unlock tactical perk 8
Unlock demolition perk 3
Unlock stealth perk 6
Unlock stealth perk 4
Unlock assault perk 4
Locate the underwater stash
Unlock assault perk 8
Unlock assault perk 3
Unlock tactical perk 4
Unlock stealth perk 8
Unlock assault perk 6
Find the Laserkraftwerk
Unlock stealth perk 5
Unlock tactical perk 3
Unlock demolition perk 2
Unlock demolition perk 1
Unlock assault perk 2
Locate the resistance
Unlock stealth perk 3
Unlock tactical perk 2
Unlock stealth perk 7
Choose to save Wyatt
Unlock tactical perk 1
Unlock stealth perk 2
Unlock stealth perk 1
Unlock assault perk 1
Save allied planes