The anime industry makes these quite often. It's a compilation, editing down the TV series to feature film length and releasing it to cinemas. I enjoyed it, but they've come up with an interesting angle that I'd have liked them to see taken a lot further.
The idea behind this film is that it's the events of the first season, but from Rikka's point of view. Unfortunately the editors weren't able to restrict themselves entirely to scenes where Rikka was present, since we'd then be missing important story beats (e.g. the introduction of new characters), but it still sounds like a cool idea to me. Firstly, I'm a Rikka fan and I think it's a positive and worthwhile development to retell a story from the girl's point of view. Secondly and more specifically, though, she's barking mad! How can you not want to see an entire movie through the eyes of a loony? I'd kill to see what the world looked like after being filtered through her head. Admittedly one wonders if Rikka-vision might not be too random to carry a film, since she often looks like an Agent of Deranged Non-Sequiteurs rather than a dramatic character with motivations. You don't want Roger Irrelevant: The Movie.
Personally, though, I'd see that as a challenge to be embraced. Do it right and it could be amazing. Besides, the TV series often switched into Rikka-vision anyway, with dragons and magical battles.
It could be done, I think. You'd need to re-animate lots of scenes almost from scratch, but it would be worth it. Besides, there's original footage in this film too. It's a story-within-a-story, with nearly half an hour of new material bookending the re-edited TV series. (Rikka's friends are asking about her life story, so she tells it from the beginning.) In other words, nearly a third of this film is new material. That could have been used to flesh out the flashbacks and demonstrate the difference between consensus reality (the TV series) and The World According to Rikka.
They don't do that. What they're doing instead is much less ambitious. I enjoyed it, but it really is just a cut-down version of the TV series. It doesn't add anything. It's just a greatest hits and not even an entirely coherent one, lacking much of the show's power and emotional weight. Mind you, I'd still call the film worth watching for the new stuff (18 minutes at the beginning, 11 minutes at the end), including a big story development that might otherwise puzzle you in season two.
What's doubly disappointing is that Yuuta's still obviously the main character. The camera watches him. We tend to see his reaction shots, not Rikka's. This is a subtle thing, but look at a story beat as trivial as Rikka being locked out of her apartment. Had that been a Yuuta event instead, there would have been shots of him trying the handle and then wondering what to do. In other words, we'd have seen his response to the situation.
Here, though, we get none of that and the first we know of it is Rikka pestering Yuuta. I've picked a trivial example, obviously. We don't care about a locked front door. However it would have been easy to splice in a brief scene of Rikka doing something like that. It would have cemented her as the protagonist. It might even have been funny, since after all we're talking about Rikka here. I'd have loved to see that... but it probably wouldn't have been popular with the fanbase. A lot of the additional material would be pretty dull, to be honest. It would just be the equivalent of different takes, with close-ups of Rikka rather than Yuuta. Even with comedy Rikka-vision, most of what I'm suggesting would have been imperceptible to the casual viewer. I still wish they'd done it, though.
That's my bitching all done. Well, nearly. The compilation probably wouldn't stand up brilliantly if you haven't seen the TV series, since it's missing character points and dramatic connective tissue. We don't learn about Rikka's dead father until her big dramatic goodbye to him, which defeats the point. Yuuta doesn't tell her to take off the eyepatch and there's no mention of him having been the original trigger for her chuunibyou in the first place. In short, what we have here is more lightweight and does less to earn its emotion.
It's funny. I enjoyed it. However it hasn't dispelled my scepticism about editing down a TV series into a movie.
That said, there are things it does well. Rikka comes alive as a pseudo-protagonist more often than you'd think, so for instance her romantic confusion works, as does the ensuing comedy of her trying to use shoujo manga cliches. (So doomed.) Besides, the original show is entertaining enough that even this cut-down version is still a lot of fun.
The original material is worth discussing too. The wedding is ridiculous. They're too young! Don't they realise how much weddings cost? However you soon realise that it's taking place inside a nutter's head, at which point you stop taking it seriously and start enjoying things like the creepy, unique Black Flame Dragon. The Shinka-Dekomori homoerotic subtext is still there, season two's living arrangements get set up and there's a brief post-credits teaser with Satone Shichimiya.
I've been harsh about this film, but I definitely enjoyed it. I'd have been happier had it done something else, but in saying so I'm criticising a cat for not being a horse. It's a compilation movie that also happens to include more than an episode's worth of bonus story. I'd have been very grumpy indeed had I not been able to find it. It's clearly inferior to the TV series, though.