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.
Choose to save Fergus
Solve the fourth Enigma code
Solve the third Enigma code
Solve the second Enigma code
Solve the first Enigma code
Collect all gold items
Collect all letters
Unlock assault perk 7
Unlock demolition perk 5
Unlock demolition perk 4
Unlock demolition perk 7
Unlock demolition perk 6
Unlock demolition perk 8
Unlock assault perk 5
Unlock tactical perk 7
Unlock assault perk 4
Collect 25 gold items
Unlock demolition perk 3
Unlock assault perk 8
Unlock assault perk 3
Unlock assault perk 2
Unlock tactical perk 6
Complete game on any difficulty
Complete game on I AM DEATH INCARNATE! (or ÜBER)
Complete game on ÜBER
Release friend
Unlock demolition perk 2
Defeat the London Monitor
Unlock tactical perk 5
Unlock assault perk 6
Unlock stealth perk 4
Unlock tactical perk 4
Locate the underwater stash
Unlock stealth perk 8
Unlock tactical perk 8
Unlock demolition perk 1
Unlock stealth perk 6
Find the Laserkraftwerk
Unlock tactical perk 3
Locate the resistance
Unlock stealth perk 3
Unlock stealth perk 7
Unlock stealth perk 5
Unlock tactical perk 2
Choose to save Wyatt
Unlock tactical perk 1
Unlock assault perk 1
Unlock stealth perk 2
Unlock stealth perk 1
Save allied planes