Realities can be anything the GM wishes. Any kind of weirdness you’ve ever encountered in a horror movie, fantasy novel, or cyberpunk video game can be brought to life and become part of the campaign. More, the campaign background enables the GM to experiment with various Realities.
GM’s can introduce any kind of Reality they wish, because if they don’t like it, the players don’t like it, or it just doesn’t work out, the portal closes and it goes away. (Conversely, if people love it, it can stick around longer.)
Sketch Realities, worlds with very little development put into them, become practical options. If they only affect one or two adventures, and then only obliquely, there’s no need to spend weeks or years carefully devising an intricate mythos.
There’s a lot of flexibility built into the campaign, and GM’s have a lot of options. This makes it very easy to plan an incursion and use one to generate an adventure.
But the adventure template is very simple: An incursion occurs. This causes problems. Players investigate. (Then kill Evil, take its stuff, and do it again next week.)
Within that template, GM’s can tweak the campaign to their heart’s desire. That’s The Infinity Files.
[Continued in Part VII.]