The timeline of events is fairly straightforward. However, which universe each game takes place in is a bit more fucky. Firstly, anyone saying there's a regular and mega universe or timeline or whatever is just blatantly incorrect, we've got outstanding evidence that each version is probably their own universe and probably even more than that. I could go down a laundry list of examples over the entire franchise but BW alone basically illustrates every single point I want to make perfectly.
>Each version is it's own universeAs documented in this GameFaqs thread
https://gamefaqs.gamespot.com/boards/989552-pokemon-black-version/59042387I want to note the exact phrasing of this
"I've heard that in another world, there's another Opelucid City that looks very futuristic."
"I've heard that in another world, there's another Opelucid City that looks very old-timey."
This isn't something that's used very often, and BW is so stiffly translated that it probably uses the exact same words consistently in Japanese if you want to go check. So keep "another world" in mind, maybe check a Japanese text dump.
>Events of other games happen regardless of what version you're playingIn both Black and White, which we've established are different universes, Cynthia mentions events from Platinum
https://bulbapedia.bulbagarden.net/wiki/Cynthia/Quotes#Pok%C3%A9mon_Black,_White,_Black_2,_and_White_2"You certainly bear a resemblance to that Trainer who faced Giratina..."
While technically the player could have faced it in DP, Cynthia was only there for it in Platium so there's no convincing explanation for why she would know otherwise.
This isn't even getting into how many different universes we see in USUM, it makes Zinnia look fucking insane by just seeing one other one.
There's one more thing that's insanely dubious and the thread autist will get mad at me for bringing it up but I really feel the need to so I'll do it in a separate post with enough asterisks to placate him.
