I'm fascinated by how they handled the man behind the curtain. It's Kang - but not Kang the Conqueror. It's a version of Kang that wanted to stop his more-rapacious alternate-universe selves from conquering the multiverse, and maintained the singular timeline so that they couldn't show up.
And now he's dead, which apparently means none of it ever happened, and all of his warmongering twins can come out to play.
(Which, of course, opens the door for Doctor Strange and Ant-Man and the Wasp, and for the Fantastic Four and X-Men to join the MCU, and for the next Spider-Man movie to do interesting things, and...)
TIL Sophia di Martino, who played Sylvie, had a newborn baby to care for while Loki S1 was filming - and so the costume designers added hidden zippers to her costume so she could breastfeed and pump during breaks in shooting.