Kamen Rider Reiwa: The First Generation

A Kamen Rider movie with a strong, character-based story... that depends a lot on having watched 01. Despite being a Zi-O/01 crossover, it's very much a part of the latter's story, with the Zi-O characters there to enable the time travel plot. That said, it makes some strong, Zi-O-y statements about the Kamen Rider franchise as a whole. It feels a bit padded-out for the intended running time, but if you're into KR, you'll probably appreciate it - specifically in the context of 01.