Test audiences didn't like Across the Spider-Verse's original ending, so its directors took a leaf out of Star Wars' book
If in doubt, watch Star Wars.
Spider-Man: Across the Spider-Verse's ending was apparently a bit of a last minute addition after test screenings were negative, and it all came together thanks to Star Wars.
Spoilers ahead for the ending of Across the Spider-Verse, obviously.
It's pretty safe to say that Across the Spider-Verse is very much a middle movie. While it does do interesting things in its own right, the final 20 minutes or so had to do a lot of legwork to set up the upcoming threequel, Beyond the Spider-Verse. Those of you that have seen it will know that in attempt to get home, Miles Morales actually ended up the universe that the spider that bit him is from, where he discovers that this universe's version of him is none other than the Prowler, the villainous moniker his uncle donned in the first film. And in a recent interview with Collider, directors Justin K. Thompson, Kemp Powers, and Joaquim Dos Santos shared that the film originally ended there, with the two Miles' staring each other down.
"I think another one that would probably surprise you is the ending that you just watched, where Spider-Gwen goes out and gathers Peter B. and Mayday and Peni and Noir and Ham, and she kind of gets the band back together to go save Miles, and you're filled with hope and excitement that, “Oh, they're gonna go back,” and, “Oh, it's coming! They're gonna get the band back together,” - that wasn’t there until about six weeks before the film wrapped," Thompson explained after being asked about something that might surprise fans.
"We actually had a screening and it just ended with Miles on the bag, and everybody was just like, 'Boo!' And we went, 'Oh god, what are we gonna do? We gotta do something.' We ran back and we quickly scrambled and brainstormed and realised. We went back and watched The Empire Strikes Back again, and said, 'How did Empire Strikes Back do it?' And we realised, 'Oh, they gave you hope at the end.'"
Powers went on to explain that this quite last minute change worked out mostly because they already knew what would happen in the next scene, "so in our minds, we had the continuity, like we knew where the story was going."
While this is an interesting tidbit as to how a major sequel was tied together at the end, it's also important to remember that working conditions on the project were allegedly quite unsustainable, supposedly with some animators working more than 11 hours a day, seven days a week, for more than a year.