Thank you for the detailed evaluation!
In the hurry of writing the disclaimers in what we thought was the last minute, we indeed completely forgot about the intro. All images used there are edited versions of public domain ones. Concerning historical accuracy, everything, except the "tailor's lad" image and Franz Joseph's glowing red eyes, is a "historical" picture whose original creator intended to depict the same thing as is suggested by the narration. A section of I. Dogma from Doom (2016) (which the intro is a parody of) was used as a basis for distorting the narration voice, but that hardly counts as using it in the game.
The NPCs actually communicate the same six pieces of information, but in a way that fits their personality, to make it less boring. We'll have to improve our ESC-UX design... meanwhile, you can use ESC to skip the intro!
It's quite unfortunate that the most widely used operating system makes the creations of indie developers perceived as being viruses. Until that changes, we can learn to build for web.