A pair of high school kids pretend to be aliens and film stuff in the late 90s while occasionally breaking out into pop songs. The guy has to go back to Australia for some reason, leaving the girl to edit all the stuff they filmed into a movie, taking a nostalgia trip as she rewatches each tape.
There's a whole bunch of deeper meaning stuff in there that other reviewers have probably covered in detail, so I'll just go over what I liked: The 90s Japanese scenery, old AV equipment and those old pop songs. Definitely gonna seek out Ryoko Hirosue's discography after this. Nice trip back to yesteryear.
Anyone who watched this film and saw the text at the beginning: (fixed AUG 2022); I put that in there after spending 2hrs fixing the timing issues with several lines of the subtitles. Full explanation in the comments