So what had been suggested by K's ending was actually true, which also meant that this was waaaaay into the future compared to what most of the group assumes. I had thought that maybe Tenmyouji and Quark were maybe coming from the future, since it appeared as though most people agreed that it was late December 2028, but obviously their time was the present since Sigma knew enough to be Zero Sr and create all this stuff. My main problem with trying to figure out everything was stubbornly clinging to the idea that it had to be 2028; the red (heh) herring in Dio's ending basically cemented it.
Speaking of Tenmyouji, I had previously considered and laughed off the possibility of him being Junpei, but the hologram in Q pretty much confirmed that.
Everything else felt pretty straightforward and relatively unsurprising once a couple of false assumptions of mine were corrected, until the revelation that it was the goddamned MOON. Holy shit. Also, I had managed to completely forget about the director's office hologram and was so confused at Sigma's reflection at first!
K being in the treatment pod shocked me at first but I remembered the ongoing theme of Schrodinger's cat, and I grinned like an idiot when Akane stepped out of the suit.
Another thing that made me grin like an idiot: the "new spot on the flowchart" messages. Awww yeah, time for some nonlinear pseudo-time travel fuckery. Also, "END or BEGINNING" is the best end-of-game message.
I dunno if I completely understand the epilogue, though. The fact that the main character is voiced (as Troy Baker, who I know was younger Sigma in the OVA) seems like the most significant point. The AB game had already been played, Dr Sigma and Phi have gone back to 2028, the mission failed, and it returns to the annihilation timeline. The only way this makes sense to me at this point is that young Sigma's consciousness was kicked out of his body and into the AB game, then he's sent back to fulfill his role as Dr Sigma, but the first attempt to stop annihilation fails and he gets kicked out into the future once the plan is attempted again? But he ends up in Kyle's body somehow. Is he an extra young Sigma consciousness that ends up in a timeline in which he doesn't belong or something?