During the opening Sequence, the scenes displayed on the Blimp are scenes from the Manga that didn't make it into the Anime Adaptation, including Kaguya & Shirogane's trip to the Movie Theater & the Cosplay chapter featuring Cat-Maid Kaguya.
During the Kaguya-Chan scene, when Shirogane is comparing Kaguya's current Brain state to an Orange, the Shooting Stars flying past are the Birdson of Birdville, the Movie that Chika suggest the 2 see in the First Episode, and Shirogane's Papier-mâché Dragon that he made & stole for the Sports Festival in season 3.
Due to Production Restraints, the Overtly Christmas Themed Film winded up releasing in February in America.
Some fans were frustrated when the film received a 2-day-only release in the US after previous anime films, such as Dragon Ball Super: Super Hero and One Piece: Red & the Quintessential Quintuplets Movie received more traditional theatrical screenings in theaters.
The film primarily adapts Vol. 14 & 15 of the Manga.