How do you get 100% completion in Wolfenstein 2?

Bring 'em on with the 100% achievement guide. "Bring 'em on!" is how to beat the game. Do it or die! If you want to win the game, beat it on "Do or die!" I want you to call me Terror-Billy! You can beat the game on a higher difficulty. I'm death incarnate! The game is "I am death incarnate!" There's a song called "Mein leben." The name is Déj Vu. The person is carrying a torch. The enemy is within.