Acclaimed Flop: People were watching Ririka SOS. Ratings weren't shabby; they were pretty good, actually! But the show was meant to be Merchandise-Driven and evidently the viewers weren't buying. It probably didn't help that some of that merch was bizarre. Nurse Angel sausages, anyone?
Defictionalization: Toy shilling is unavoidable in the typical magical girl show, and Ririka SOS is no exception. The Nurse Cap and Angel Baton are obvious examples, but there are more peripheral gadgets as well, presented in awkward parades of product placement.
No Export for You: Ririka SOS aired in a few markets outside of Japan, but despite its western-friendly visuals, it's never been officially been made available in English.
Screwed By The Merchandise: The anime was doing well, however it was cut short because people weren't buying the merchandise as expected.
Yuri Amano voices both Princess Helena and Ririka's mother, Madoka. At one point Ririka seems to confuse the two. Ririka hears a disembodied voice calling her name — Helena's usual schtick — and asks aloud, "mom?"
In 1995, a flip-phone in the possession of a 10-year-old girl like Miyuki was a sign that she was wealthy and had every advantage. Now the joke is that she has a flip-phone...outside of Japan. In Japan, current viewers of the show would simply miss the significance of a girl her age having a flip-phone because they're still in common use. Japan hasn't taken to smartphones as much as other countries, to the point where you can get a smart-phone that looks JUST like a flip-phone.
Likewise, episode 7 of the anime incorporates a pager into the plot, and nowadays that is a practically a punchline in and of itself, depending on how old a viewer is.
What Could Have Been: Since the show was cut short, the staff wasn't made to set up the ending as well as they planned to. They wanted the situation to get steadily more grim.