The game takes place after the Vampire Incident but before Embodiment of Scarlet Devil.
Spellcards exist, we know the game takes place after
PC-98 but before Windows, Marisa has quit being Mima's servant, and a mix of PC-98 and Windows era characters are present. It makes sense.
If the above is not true, Route D is 'canon'-er
It consists of more PC-98 characters or characters that logically must have been in Gensokyo since the beginning and before. The Scarlet Devil Mansion didn't arrive until the Vampire Incident, the lunarians would be unlikely to know Reimu since the characters do not indicate familiarity with Eientei on the way there besides maybe Yuyuko, and while Marisa could have known about the Sanzu River location from Mima it seems the slightest bit unlikely since Mima as an evil spirit who couldn't even remember why she was evil would remember the location of a place she got dragged away from to become an evil spirit in the first place and in the other routes Marisa does not assume Reimu dead until she is told around Stage 3.
Characters playable in other games don't know what's going on unless someone tells them, and those that don't know what's going on and have to be told are independent from Reimu and wake up separately.
Marisa knows nothing about the incident unless someone tells her. Yuyuko is aware, but specifically mentions Youmu having no idea. Sakuya is still cleaning the mansion like normal and Remilia does not know what's going on, nor does Meiling beyond Flandre escaping. Patchouli tells you Reimu is dead but does not deem it necessary to tell Marisa anything more beyond Reimu being special and thus significant. We see neither hide nor hair of many
Po FV characters besides IN debuts and Medicine, Aya, Komachi, and Eiki, of whom Komachi doesn't say anything, Aya doesn't appear to care Reimu is missing and possibly dead, Medicine continuing poison-gathering like normal, and only Eiki who might have judged Reimu to go to Hakugyoukurou quickly at Yuyuko's request seems to know that Reimu even died and where she went. It is possible the Team 9 grade minor characters and phantom ensemble all weren't strong enough to stay in the dream until the bitter end and escaped, though. Reisen doesn't say anything (and Eirin and the hourai immortals don't know either, but they are too busy medic-ing or fighting anyways), but Tewi knows only because someone has to and she's been on Earth longer than any of them and would likely know. Yuuka doesn't tell you what's going on despite being 4th-wall-breaking and generally Yuuka Kazami, because she was a playable character in the PC-98 era, and the same applies to Mima. Yukari and Yuyuko know because Reimu told them when she died. Alice and Shinki are from Makai and are thus explicitly foreign to having to die. Suika is not seen until the Extra and Phantasm stages where she saves Gensokyo.
Makai is a totally independent area.
Alice actively mentions the gate to Makai is closing and implies that it will survive Gensokyo blowing up by that and asking Marisa to come to Makai and not die over Reimu dying. Plus, Marisa has apparently grown much stronger since the last time Alice and her fought according to Alice, so if Alice at full power is stronger than Shinki and still gets crushed, Shinki doesn't have to lose any power to lose so bad she gets tied up and blasted out of the sky, nevermind Reimu's death. Since Shinki was expressly mentioned to create Makai in Mystic Square, we can assume Makai is either a dream that is not dead yet (and Shinki might be lucid dreaming a little), or a dream-transcendent-into-reality like Gensokyo after the campaign.
Yukari had a secret plan, the opposite of Marisa's suggestion to Alice.
Instead of taking Makai to Gensokyo, Yukari planned to take Gensokyo to Makai.
Gensokyo is likely smaller anyways (Makai is an infinite world of demons and Gensokyo is a patch of land taken from Japan), we know Makai will survive Reimu's awakening from the above WMG, and the gate stays open until at the very least the end of Stage 3 Route D, and if Yukari manipulates the boundary between Gensokyo and Makai she could probably force it open by keeping the boundary existing until Gensokyo was gone.
Yukari maintains the ability to use gaps until the very end, considering she teleports during Beauties of Gensokyo the midboss card before Reimu. Since once Reimu shows up Yukari and Yuyuko go away, leaving no stage fairies, we can assume Yukari rescued everyone and everything she could (with the obvious exception of Reimu who probably would not leave the dream while it was ending and Marisa who wouldn't go until she'd beaten Reimu up at the bitter end and the possible exception of a bit of Suika to reconstruct Gensokyo when all was said and done and some fixed objects in what remained in Gensokyo like the sun setting in the Netherworld indicating the final day of Gensokyo) to Makai and gave Reimu the all-clear signal to feel free to fight before the final sundown.
In the Extra and Phantasm stages, Suika reconstructed Gensokyo, and shortly afterwards Shinki or Yukari reconnected and returned everything to Gensokyo.
Yes, this is just to give the game an unabridgedly happy ending.
After Suika managed to rebuild Gensokyo by gathering it's fragments and also rescued everyone from oblivion (except for PC-98 characters who were gone for good including Mima) everyone hated Reimu for allowing this to happen to Gensokyo when she was their supposed protector, so for a time they frowned uppon her, donated even less to the shrine and eventually, even if they got over it now being more a solid world than a real work... Faith in hakurei was lost, which explains why in Mo F the Hakurei orbs' power now is only good for bullet cancel, so that Reimu has to work hard thorough scarlet weather rahpsody, mountain of faith, subterranean animism and undefined fantastic object to recover the lost faith and make the hakurei orbs powerful once again.It was then when Kanako came from the outside world, sensing the faith crisis and finding a perfect oportunity to let her plans unfold and save herself from a faith crisis that would afect her on other ways. Leadng to the events seen in mountain of faith.
Everyone acts like the dream apocalypse event never occurred because Keine and Akyuu worked together to wipe out the memories of everyone except for few people including Marisa, Yukari, Remilia and some other select ones, but also coming to an agreement that the incident is a hard taboo and must be zealously keep as a secret from everyone.
- Hey, maybe that's why Mo F Reimu is a zombie!
