The main difference between DC and Marvel comics used to be that DC was a lot more invested in parallel universes. That started all the way back in 1956 when DC brought back The Flash but as a new character with a new costume and then sometime afterward re-introduced the Golden Age Flash as a separate character still living in a parallel universe from the main (Silver Age) Flash. They also used this to explain the vast power discrepancy between the Golden Age Superman and the contemporary Superman who could survive atomic bombs. This in turn led to a whole bunch of parallel universes until DC finally destroyed them with Crisis on Infinite Earths. For a while.
Marvel really didn’t go for that sort of thing; for the most part, before the creation of the Marvel Cinematic Universe and the use of other properties (like Spider-Man) by Sony and other producers, everything including the World War II history was in a single timeline. But for a few years, Marvel Comics came up with an “Ultimate” line of comics where their main heroes were re-imagined as different people (this is where they came up with the idea of casting Samuel L. Jackson as Nick Fury). The Ultimate universe eventually got re-absorbed into the main (‘616’) Marvel Universe, but the Ultimate Spider-Man, a black Puerto Rican teenager named Miles Morales, was popular enough to where they kept him in the main universe. All of this matters in that the premise of Spider-Man: Into the Spider-Verse has to deal with the merging of parallel universes, and the appearance of various other alternates like Spider-Gwen (Gwen Stacy in a universe where she got the spider-powers instead of Peter Parker), a 1930s Spider-Man, an anime Spider-Man and of course, Peter Porker, the Spectacular Spider-Ham.
So while the movie will do a good run-through of character backgrounds, it really helps if you’re already familiar with the comicbook source material, but then most of the people already wanting to see this probably will be. As the story goes, I am not sure why the villain they chose, as much wealth as he has, would be the one funding a dimension-crossing supercollider, but his motivation is at least plausible. Otherwise Miles experiences a not atypical hero’s story where once he finds his own spark, he realizes that “anyone can wear the mask.” Which when you think about it, is also the message of V for Vendetta. But that’s another discussion.
The important thing about this movie is that if you’re going to see it, do it soon because it NEEDS to be seen in a theater. The level of detail on the animation for this movie is just phenomenal. At least as good as the Lego movies. I’d heard that based on its win at the Golden Globes, it might be eligible not only for Best Animated Film Oscar but even Best Picture. I’m not sure about Best Picture, but Into the Spider-Verse definitely needs to be recognized as an innovation in film.