As the summary said, this is a recap movie. Which is actually pretty weird. Considering, why did they bother to make a full-length movie just for a recap of season 1? My best guess is, this movie consists 3 parts which shortly describe: a recap of season one, an epilogue of season one, and as a early prologue of season 2. All the main plot elements are served in this half and a hour movie, with a lot of cut towards the secondary plot/subplot, like "Isshiki's heroic moments" for instance. This type of execution is not all that strange actually since Stand Alone Complex didjust the same thing... twice. So, it is best to enjoy this movie as a sort of nostalgia rather than watching all 12 eps long of season 1. New elements do exist. Like a new footage during the prologue and epilogue. A new opening and ending and a bit of after-credit.

What you want to expect from this movie is, top notch animation, delicious sound direction and voice acting, top notch animation, and a bit of reminiscent of how sweet the Chuuni romance from season 1. Did I say animation twice? Well, because all the nuance which brought the show alive are mostly from this department. They also a bit condensing some of the unnecessary elements which helps a lot in enhancing the enjoyment. I found myself quite enjoying it during some of the scenes, and not so much in the other (this a recap, duh).

So, there is not much to tell from a recap. But if you enjoying the first season and want to be reminded why you liked the first season, Takanashi Rikka Kai: Chuunibyou Demo Koi ga Shita! Movie might help lead you to the world of season one without troubling you to marathon the whole season again.