I watched this film twice, and both times have really left an impact on me at the end. For me it is an amazing story about self-determination and accepting ourselves.
At the beginning it can be difficult to familiarize with the direction, which is a bit different from most typical dramas, but I really loved it. It really is one of the best direction that I have ever seen in a japanese drama.
The director also did a wonderful work into adapting the manga into the live action, and in my opinion in this movie the introspection of some characters (like Akane, for example) is better than in the manga itself. Nevertheless, some parts are explained a bit quickly, but I think it is due to the lack of usable screen time in the film.
The cast also does a very good job into representing the characters on screen. I absolutely recommend this film (despite the bad rating and reviews that it generally has on internet), and if you want to understand better the story I recommend reading the manga before watching the movie.