Cavalary: Shouldn't it be a contender for GOTY 2021 though, since nobody'll be able to actually finish it, without cheating, this year to actually be able to say how the whole thing is?
Not a huge fan of high-iq considerations myself because I like being dumb but let me tell you that even after less a minute of playing the game the entire point is that interacting with the game, questioning your actions (as in, progressing/moving about) and contemplating due to its slow pace. The ending itself (revealed during the beginning of the game, waking up king reveals one of the endings) serves as a hook to make players interested. Questioning (and figuring out) whether or not the ending may even matters is part of the fun and the overall experience with the game. Or at least in my point of view, you're playing as something undefinable (refered to as "shade" in game) after all.
If anything the ending will only serve as a state to seperate the two modes, playing the game and not playing the game (it is "always" running even after turning it off) with something else that can be clearly defined. Or in other words, the game began with something, so it must end on a similar note. In this way its not really a open-world game, at least compared to traditional paradigms.
The games theme, after reading the description and playing through the intro is "how to cope with nihilism". So all things considered, I do think that even if you experience the game without touching it almost the entire time you can still give a reasonable assessment even without considering the ending, nor caring about it at all.
And besides, the description of the game says something about multiple playthroughs so perhaps it takes 2400 days to see the entire game so you see all endings or something like that :P.