TL;DR - This movie is basically the final episode of the third season, so if you've watched it then watch the movie too to see how it concludes. If you haven't watched the third season you really need to watch it first, otherwise you wouldn't understand anything. The movie follows Bifrost's final scheme. While govt. Karina Komiya is in the public safety bureau building, the entire building locks-up, all doors, both internal and external, are locked, all means of communications are shut-down and several people are taken hostage. It seems that Bifrost are going after Komiya's head. With surrender not being an option, the teams mustfind a way to take back control over the building and find Bifrost's first inspector, Kouichi Azusawa, who appears to run the scheme as though it were a game.
I'm giving this movie a slightly higher score than the third season since it's a step up and climax, and also since it finally explains some of the mysteries of the third season. It's also a good thing that no new characters are unnecessarily introduced and that some veteran characters are given more screen time, namely Mika Shimotsuki and to some extent Shinya Kougami.
Comparing to the previous movies (the first and the 3 "Sinners of the Case" movies) this is by far the best one, but it still not as good as the first season (at this point I'm not sure whether any future season or movie will).
Art it same as always. Sound gets a perfect 10 for good use of 5.1 surround.