I've been a fan of Mahouka Koukou no Rettousei for quite a bit, even if I didn't read the novels and stayed with the manga and anime.
First off, I'll be quick because other reviews go more in depth.
This film is clearly NOT the direct following of the anime and doesn't appear in the manga, so it's a side-story which is quite enjoyable, taking place during the vacations.
STORY:
The story is ..ok?... but quite simple in the end. When I say simple, I also mean that you can clearly feel the shonen wibe behind the interactions and it's really easy to understand the story. (So it's quite lighthearted without the "POWER OF FRIENDS" part of the shonen shows.... but lighthearted in the wrong direction, leading to situations with no sense at all because the logic disappeared in the stratosphere...)
ART:
The art is GREAT, you can't argue with that. It's not as good as Violet Evergarden or Ghibli films, but it's still in the right continuation from the series with overall better graphics, but a better spirit. You can feel that it's a movie and not a TV series with lack of time. The CGI is quite well used, or used in the background, so it doesn't scratch your eyes.
CHARACTERS:
The characters are like before (in the TV series), but with little to no character developpment for the ones we already get to see in the previous anime AND characters appearing way later in the novel/manga series (which will not be presented, so it's kind of laking for the people coming from the anime TV part).
SOUND:
The sound was ok, but not particularly good or memorable. It just did it's job without giving a special wibe or atmosphere, which is kind of sad.
ENJOYMENT:
The movie is nice. If you liked the anime series, you'll definitely like this movies... and if you are a big fan and you read the manga/novel, you'll probably like it even more.
OVERALL: (8/10 for MAL, 8,2/10 precisely)
This movie is laking a great sountrack and a better character introduction, but in the end, it was quite what I was expecting from a mahouka-movie. It wasn't a masterpiece, it wasn't GREAT in capital letters, but it was enjoyable... and more enjoyable than most of the current movies coming out in the regular cinema industry.
People coming from the anime series ONLY will have scenes they don't understand, because they don't know the characters, which are introduced a bit later in the original series.
If you liked MKNR, I definetly recommend you to give it a shot. The animation is still great and Tatsuya is present (without him, the movie wouldn't exist after all, he's kind of the main character).
Hopefully, this quick review was helpful.
(Note: for me, 7/10 is the average not of an anime which hasn't really hardcore flaws. If everything is decent, the anime will get an 7/10 from me. 8/10 is already way better and 9/10 is nearing the realm of masterpieces.)