These achievements can be achieved simply by playing the game.
Saving Annette or Kessler can be done by replaying the mission.

Undercover
Infiltrate Castle Wolfenstein
When entering Wolfenstein you get your first achievement.

Freedom
Escape Castle Wolfenstein
Near the end of chapter 4 you will recieve this achievement.

Revenge
Complete part one
You will recieve this achievement in the begin of chapter 5 in the boat

Annette saved
Choose to save Annette
This happens in chapter 6, go left to save Annette. Replay the mission to save Kessler later.

Kessler saved
Choose to save Kessler
This happens in chapter 6, go right to save Kessler. Replay the mission to save Annette later.

Click here for a screenshot of the location in which you must make your decision.

Hero
Complete game on any difficulty


Super Hero
Complete game on I AM DEATH INCARNATE! (or ÜBER)
If you finish the game on ÜBER you will get this achievement plus Über hero achievement.

Über hero
Complete game on ÜBER
When playong on Über, just play slow, use cover and try to keep it stealth mode.

Yes you can replay the last mission on a higher difficulty and get the achievement and save time.
But a real gamer would offcourse replay the campaign and test his skills.

All these achievements are related to getting your perks in the game
If you want to see the progress go into Journal (default J) click on perks and have a look.

Health upgrade I
Unlock the Health upgrade I perk
Overcharge your health to reach 200
In the research lab check behind for allot of health, or simply at the start of chapter 3.

Health upgrade II
Unlock the Health upgrade II perk
Overcharge your health to reach 250
In chapter 4 when you meet Annette and Kessler you find allot of health.

Health upgrade III
Unlock the Health upgrade III perk
Kill 5 enemy's in a row whilst overcharged
In chapter 4 you must defend the house whilst being overcharged, it should be easily done.

Armor upgrade I
Unlock the Armor upgrade I perk
Collect 100 armor helmets

Armor upgrade II
Unlock the Armor upgrade II perk
Overcharge your armor to reach 200
In chapter 3 in the bedroom area in both bedrooms you will find +75 armor (1 is hidden)

Eagle Eye
Unlock the Eagle Eye perk
20 silent commander kills

Tough Skin
Unlock the Tough Skin perk
10 pipe head explosions
In chapter 6 when zombies appear, hit them on the head.

Vampire
Unlock the Vampire perk
25 stealth takedowns

Kampfpistole ammo storage upgrade
Unlock the Kampfpistole ammo storage upgrade perk
50 kills with the Kampfpistole

Bombenschuss clip upgrade
Unlock the Bombenschuss clip upgrade perk
50 kills using the Bombenschuss

Schockhammer clip upgrade
Unlock the Schockhammer clip upgrade perk
50 kills with the Schockhammer

Ammunition upgrade
Unlock the Ammunition upgrade perk
100 Dual-Wield kills

Reload mash
Unlock the Reload mash perk
20 kills with the last bullet of a clip
In Chapter 6 you get a shotgun, this is the most ammo friendly way to get the achievement.

Quick turn
Unlock the Quick turn perk
50 kills from cover

Grenade belt
Unlock the Grenade belt perk
Kill 3 enemy's with 1 nade
In chapter 6 after you drop out the house, nade the bunch of zombie's.

Carry heavy machinegun
Unlock the Carry heavy machinegun perk
200 kills use the MG46
In chapter 7 you need to go on foot threw a door, this is the best place to hoard kills.
This perk could be useful against the End Boss in Chapter 8.

These achievements can be achieved when you collect items.
Collectibles are gold bars and letters. (Tip: unlock Eagle Eye perk, this will highlight collectibles )


All that glitters
Collect 8 gold bars


Glittering gold
Collect 16 gold bars


The ecstasy of gold
Collect 32 gold bars


Gold master
Collect 64 gold bars


Paperboy
Collect 5 letters


Postman
Collect all letters


With Eagle Eye unlocked, collectibles will appear as a ? on your map.
Press M for the map.

When you have all gold bars, you will have the option for golden pistols.

These achievements can be achieved when playin challenges.
Challenges are unlocked by playing the main story line.


Tip: To obtain Gold, you must be playing on "I Am Death Incarnate" or "Uber" difficulty.
(Hover your mouse of the challange, press E to change difficulty)

Research centre combat master
Achieve gold medal for this challenge map
Obtain a score of 11.300 or higher ( 00:00 )

Prison docks combat master
Achieve gold medal for this challenge map
Obtain a score of 29.800 or higher ( 01:30 )

Keep foyer combat master
Achieve gold medal for this challenge map
Obtain a score of 24.500 or higher ( 05:23 )

Cable car platform combat master
Achieve gold medal for this challenge map
Obtain a score of 26.600 or higher ( 08:20 )

Caves combat master
Achieve gold medal for this challenge map
Obtain a score of 26.900 or higher ( 12:57 )

Paderborn bridge combat master
Achieve gold medal for this challenge map
Obtain a score of 22.800 or higher ( 17:57 )

Wulfburg square combat master
Achieve gold medal for this challenge map
Obtain a score of 17.600 or higher ( 22:42 )

Workshop combat master
Achieve gold medal for this challenge map
Obtain a score of 17.200 or higher ( 26:54 )

Bathhouse combat master
Achieve gold medal for this challenge map
Obtain a score of 17.100 or higher ( 29:02 )

Graveyard combat master
Achieve gold medal for this challenge map
Obtain a score of 28.800 or higher ( 30:45 )

Make sure you keep the combo going for more points.
And headshots will also give extra points.

You will also need to trigger alarms and let them keep ringing to get more points!

Nightmares can be found in the main story line.
This video will show you all locations of the Nightmares


German Alps nightmare
Complete the prologue nightmare
00:00 Prologue - German Alps nightmare

Prison nightmare
Complete the nightmare in chapter 1
00:50 Chapter 1 - Prison nightmare

Docks nightmare
Complete the nightmare in chapter 2
01:32 Chapter 2 - Docks nightmare

Wolfenstein Keep nightmare
Complete the nightmare in chapter 3
02:14 Chapter 3 - Wolfenstein Keep nightmare

Escape! nightmare
Complete the nightmare in chapter 4
03:20 Chapter 4 - Escape! nightmare

Wulfburg nightmare
Complete the nightmare in chapter 5
03:30 Chapter 5 - Wulfburg nightmare

Ruins nightmare
Complete the nightmare in chapter 6
03:56 Chapter 6 - Ruins nightmare

Old town nightmare
Complete the nightmare in chapter 7
04:37 Chapter 7 - Old town nightmare

Guten tag!
Complete the nightmare boss level
05:28 Chapter 8 - Guten tag!

Guten tag!
Complete all nightmare levels