Originally, Kyoko and Godai's relationship wasn't going to be the basis of the story. Rather, Rumiko Takahashi, the creator of the comic the series is based on, was going to end the storyline early on and continue on with a series of other storylines centering around the building's other occupants. However, the romance storyline proved so popular it became the basis for the entire series in both comic and television form.
The original opening and ending for ep. 26 ("Alone Again, Naturally" and "Get Down," both by Gilbert O' Sullivan) are not included in the US release of the TV series. This is because Viz was unable to secure clearances for the two songs.