Aside from the inverted skyline, the only giveaway that something is off in one of the most striking images of “Spider-Man: Across the Spider-Verse” is the ponytail that’s sticking straight up in the air. Gwen Stacy (voiced by Hailee Steinfeld) and Miles Morales (Shameik Moore) have just reunited in the “Into the Spider-Verse” sequel. After giddily swinging through New York skyscrapers, they perch themselves on the underside of a clocktower ledge. Their view is ours: An upside-down city, shimmering in the distance.