Welcome to GamesRadar’s Week of Wolfenstein. Achtung, and prepare yourself for five days full of injured Nazis, delicious dog food, secret rooms, and mecha-fascists as we celebrate all that is pure and good about fighting the Third Reich. Today, we’ll be kicking things off with some essential factoids that all self-respecting Wolfenstein fans should know by heart - but probably don’t. So scroll on for obscure trivia lurking in Wolfenstein 3-D’s occult background, and come back throughout the week as we continue celebrating the past, present, and future of the first great first-person shooter.

Returning to Wolfenstein years after it released brings back mixed memories. The worst: spending countless hours mashing the spacebar while pressing up against every wall until we were certain we uncovered all the secret rooms. The best: finding the secret Pac-Man level on the seventh floor in Episode 3: Die, Fuhrer, Die!

Above: Forget Mecha-Hitler. These wobbly-eyed ghosts were the most dangerous Wolfenstein enemies. Touching them meant instant death 

From the dark blue wall tiles to the way the level was littered with Nazi gold where the Pac-Man pellets would be, this surprising secret level suggests that Wolfenstein’s Nazis were up to much more than manufacturing mecha versions of their mustachioed leader.

Above: A map of Floor 7 from Episode 3 to help you get to the super secret Pac-Man level. Head here for more maps crafted by Christopher Long

Above: Wolfenstein 3-D’s bloody homage to the arcade classic 

Above: See the super secret Pac-Man level in motion

By the time Doom introduced gamers to the joys of wielding a chainsaw, Wolfenstein 3-D had already carved its place in the canon of PC games. So it’s fitting that Doom II: Hell on Earth featured a gory recreation of the very first level in Wolfenstein 3-D.

Above: While we’re at it, let’s compare BJ Blazkowicz’s always arching eyebrows against the furrowed brow of Doom’s space marine 

It’s true. Dragging bodies out of sight, changing uniforms, and performing silent kills might have given you a taste of what Solid Snake and Sam Fisher would have to offer years later. Although these features were completed, they were eventually removed because they over complicated the control scheme and slowed down the game’s pace.

Above: Hints of the stealthy shooter - that might’ve been - can be seen in the title screen. Look how sneaky! 

Above: Although you could give a grunt a good scare if you snuck up behind them, Wolfenstein 3-D might’ve been so much more