This is something that caught my eye when watching a video on Der Riese recently. I didn't give it much thought, and unfortunately, I can't give much more than just thought. But if you look into the sky, there is a black star. I believe this is the mystical 'Night Sun', or Nachtsonne, as it is called in German. It is also known as the 'Black Sun' in English as well as the Night Sun. It has several links with the occult, and could actually suggest that the Nazi Zombies story is ongoing in another galaxy or dimension or something. The Nazis were fascinated by the occult, and the Nachtsonne was the jewel in the crown of the occult, from what I can see. Amongst uses, it was a Nazi occult symbol as I said above. However, it is also still used by pagans in Germany today, according to Wikipedia. Now... we shall advance this absurd theory of mine some more:
Die Glocke. The Bell. German experiments that were kept top-secret. What is meant to give you the Type 99? Yup, hitting a bell. The Nazis were working on a Wonder Weapon, or Wunderwaffe, as many people will know it. Owing to the fact we can't use the T99 and nobody has an idea what it would be like Pack-a-Punched, could it be another Wunderwaffe? Maybe not the standard version of the weapon, but when PaP'd... maybe... just maybe, we're onto something.
One of the beliefs about the Die Glocke experiments is that it could re-animate the dead. Zombies are re-animated corpses. Coincidence? Probably not. Now, this part is going to be made as obvious as possible. The SS scienttists working on the experiment worked at a facility known as The Giant. Want that in German? DER RIESE. Time and space manipulation was meant to be another part of the experiment. Considering the fact that the Nachtsonne is above Der Riese, could this be set in a situation where the experiments had been successful, and there was an alternate space and time continuum? Now, I don't know if Red Mercury or Xerum 525 are present in the game referencing or not, but it seems likely to have something to do with it all.
More to add to this idea of mine: there was a meeting held between the heads of the secret societies, such as the Thule Society. The men present were discussing a message they had apparently received... from a completely different space system, called Aldebaran. Aldebaran is in the Taurus cluster, and is the brightest star. The name is Arabic for 'The Follower'. The Nazis followed the Nachtsonne and saw it as a valuable piece of the occult. Plus the Nachtsonne is meant to be a star that burnt out over time and has become invisible. Should Aldebaran burn out it could become a black sun...
The Germans worked on a testing-bed for their experiment known as the 'Fly Trap'. Wasn't there a Fly Trap in Der Riese? The experiment was in Siechnice. This is a direct quote from the page as I'm lazy, and this gets it across perfectly:
In his book, Hitler's Suppressed and Still-Secret Weapons, Science and Technology, Stevens wrote about a conversation in the early sixties between a friend's father and his boss at NASA, Otto Cerny, a German scientist from Operation Paperclip. At first Cerny was only vague about his previous work, dismissing it as "weird experiments on the nature of time". However, he later drew a structure made of a circle of stones with a ring around the top along with a second ring from which something hung. At some point during the conversation Cerny described similar to a concave mirror on top of the device allowing "images from the past" to be seen during its operation. He claimed that it was possible to "go back and witness things", but not to go forward
One of the things written is that the Wunderwaffe is the DG-2. DG=Die Glocke? Possibly. Now, the italicised piece above might not have any bearing, but it is a fascinating read. Maybe someone could add to this part of my inane theory?