Two Nintendo videogame platforms can be seen in the room in which Mitsuha and her friends plan their actions late in the film: a Famicom (known in the West as the Nintendo Entertainment System) and an orange Gamecube. Both of the shown designs were exclusively available in Japan.
In the scene where Mitsuha and her friends are planning their action with town's early warning system on Katsuhiko's desk there is a rare and old, sold exclusively in Japan home computer present: a Sharp X68000. This is the same characteristic computer used by Daru Hasida in Steins;Gate (2011), a famous anime also about time travel.
The film is inspired by the Japanese tale "Torikaebaya Monogatari," where a brother and sister live their lives as a woman and man, as well as Greg Egan's Sci-Fi story "The Safe Deposit Box," where a man lives his life as different people, and the Japanese gender-swapping tales "Torikaebaya Monogatari," "Inside Mari" and Ranma ½ (1989).
There have been rumors that director Writer director, Makoto Shinkai originally planned to end the film with a bitter ending; the two protagonists, Mitsuha Miyamizu and Taki Tachibana can't find or realize each other and go their separate ways in the end. The rumor said that distributor Toho argued against his idea and ordered him to change it to a happy ending as shown in the competed film. To disprove this rumor, Shinkai posted a screenshot to his Twitter of his working draft from 2014 showing his ending as presented in the film and novel was always planned.