I loved it. I love Love, Chunibyo & Other Delusions!, but I also specifically loved this film. It effortlessly recreates the charm of the TV show, as if we'd never been away, and it's finding a new (but correct and indeed definitive) answer to the show's big question.
Here's the franchise so far:
2011-17 = four light novels... only four? Wow.
2012 = anime Season 1 (twelve episodes) and six short internet Lite-isodes
2013 = OVA Christmas episode and a compilation film that retells Season 1 from Rikka's viewpoint
2014 = anime Season 2 (twelve episodes), a thirteenth OVA episode and six short internet Lite-isodes
...and then this film popped up out of nowhere. I'm happy that it did, of course.
The premise is that Rikka is a total loon who can't say two sentences without talking about her dark magical powers, claiming to be the world's most powerful wizard and/or saying cool-sounding French and English words that she doesn't understand. This is called chuunibyou. (There are other variants, but it generally involves reality-resistance and/or declaring that you're awesome.) The traditional age for it is 14, but Rikka's still a hardcore case at age 18.
Amazingly she's managed to acquire a boyfriend (Yuuta), but he used to be a chuunibyou himself and had been trying to hide that when they met. It took him ages to stop cringing at all things Rikka-ish. Their other friends include Shinka (another easily embarrassed ex-chuunibyou) and Dekomori (as crazy as Rikka), who will probably end up in a lesbian relationship together, but they drive each other bonkers and are always fighting.
Oh, and there's also a pink-haired girl. I couldn't remember who she was, but she's from Season 2.
To be honest, you could lock these idiots in a cupboard for 94 minutes and I'd still watch them. They're lovely. They're endlessly funny. Rikka has an older sister (Touka) who's sane and scary, so of course she's the enemy here. (She's doing it all to help Rikka, admittedly, but our heroes disagree with her methods.) Will Rikka be moving to Italy? Surely not? She and Yuuta had been planning to go to university together, but unfortunately this won't work unless Rikka does some studying. Rikka doesn't like schoolwork, because schoolwork doesn't like her. It disrupts her magic powers. If you gave Rikka a choice between doing her homework and having a leg amputated, she'd probably want to think about it.
One idiot thing leads to another and soon our heroes are in a road movie. Rikka and Yuuta are on the run from Touka, who's blackmailing Shinka and Dekomori into joining in the chase. (This is very funny, but not the most productive move on Touka's part. You'd probably get better results from reading tea leaves.)
The film's about the Rikka-Yuuta relationship, with Shinka-Dekomori in the background as thematic counterpoint. Since the very first episode, people have been asking if Rikka's going to grow up. Is having a boyfriend good for her, or is Yuuta just enabling her delusions? Will she still be like this in ten years' time? Should she change, or stay the same? Is she herself thinking about that at all? (The answer turns out to be "yes", in her Rikka-ish way, and you can actually understand her reasons for being scared of either option.) This is the elephant in the room, obviously, but of course we don't want her to change. We love Mad Rikka. She's funny and we've seen what it does to her when she tries to be normal. Is she the one who needs to change her thinking? I liked the ending a lot, on reflection, and you could even call it mildly subversive for anyone who'd dismiss Rikka's behaviour as "on the run from reality" and just a problem that's waiting to be fixed.
Another major issue being addressed here is the stalled romance. Our heroes are living together as boyfriend and girlfriend, but they've never even kissed. The TV series had always been an exercise in Relationships Going Nowhere, so of course all the fans wanted that to change here. It's not hard to see that Rikka would like to take things further, but her personality is a minor obstacle and Yuuta is a major one. He treats her as if she's ten. Halfway through the film, I was wondering if he even had a sex drive at all. It turns out that he does, but that he thinks God wouldn't want him to act on it. (Bizarrely, he imagines God as Odin. Well, I suppose that fits an ex-chuunibyou.)
It's great. You might say that it's basically just fluff, but I'd disagree. It's plot-light to the point of resembling a long filler episode, but it has significance in how it moves on its characters, their attitudes and their relationships. It's also funny and charming. I know I'll be watching this again.