I see my points were ignored. Fine, I'll just add more then.
"In regards to destroying all of existence, the writer says, "Yes, or at least if they couldn't destroy all of existence, they could wipe away all the parts that mortals live in." (emphasis mine.)"
The key words here are "existence" and "mortal".
The game doesn't describe the Spiral as being all of existence , it's just the name of the universe that the Player happens to live in.
So, why does it matter that he used the word "mortal"? Because "mortal" applies to almost everyone in the franchise. Even Mellori, the Bat and the Player
are regarded as mortals , despite the fact that the Player is Bartleby's Scion, Mellori was
"pulled out of Raven's heart" and the Bat was "born from Spider's dream". The only characters who can be confirmed as not being mortal are Raven, Spider, Bartleby, the Creator and the three Titans.
"But you left out the very next sentence, which was, "Again, I'm content not to speculate until I need an answer.""
The WoG who said that wasn't the one who wrote for the quest that the feat was created from. He didn't even work on the game in that time. The fact is that the Professor refers to an alternate timeline, and seeing as how he already knew what was in said alternate timeline, it's safe to say that they exist side-by-side. How else would he have known about it?
"What info from the game itself is being used to support these ratings? Because at best, what has been shown justifies 2-C."
'2-B: Characters who can create and/or destroy 1001 to any higher finite number of universal 4-dimensional space-time continuums.'
Adding on to the alternate dimensions which we've already listed, there's also t
he Djinni dimension, the Shadow Realm, and the Astral Plane . There's also the Reverie and the alternate timelines which we've covered already.
Even if we don't use the alternate timelines, I believe the Reverie alone should be enough
for it to count as being 2-B . The Reverie itself is only the gateway between dreams, which is supported by the use of Portals, but
it itself is surrounded by various astral bodies including a black hole , which implies it's the size of a universe. So, why should dreams count as being universal in size too? It's simple: We use Mellori's dream to scale. As Zenkai said, her dream is shown to have several galaxies and stars in the background.
But how do we know that they're actual stars, and not just part of the scenery of her dream? Because Mellori dreamt up several different worlds based off of her memories for us to move around in, and they existed independently from her presence (we know that because of the fact that she keeps leaving those worlds before us and nothing breaks apart).
There's nothing to suggest that this would be limited only to Mellori's dream. The reason the Player's dream was visually different was because of his Shadow magic. Not to mention the fact that Spider trapped him inside a nightmare, which distorted things even further.