Plot: The plot is actually alright. Twins fall in love with each other and face the social stigma of it. If you can deal with incest in fiction, this movie isn't going to offend you. It could actually have been a very sensitive peace if it was made more carefully.
Technical review: Considering the cast (both MatsuJun and Eikura had solid careers long before this movie), I’m surprised it feels so… cheap? I’m not entirely sure whether it’s a matter of budget or style, but yeah. Characters have little to no make up and styling done, but that could have been a choice to make them more similar to real high school students. The clothes aren’t really fashionable nor truly flattering and Eikura sports some fried strands that makes me think they asked her to straighten her hair on her own. They made even Ayaka Komatsu look plain.
But while that could be explained as intentional, the bad light, the lack of soundtrack (several scenes in the movie that are completely silent and fail to convey a mood) and the acting itself all feel like inexperienced film-making. The dialogues were so lame that they made some key-scenes come off as awkward, and the movie is too long for such a mess. I was curious about this movie, but sort all these flaws were very glaring and distracting.
Characters: They were all just flat. Yori is angsty, Iku is naive, Yano is loyal, Kusonogi is determined. None of them are likable, or even relatable. I couldn’t feel them at all.
Warnings for the underage MatsuJun fans: This isn't by all means an indecent movie. At most, brother and sister are shown kissing, and there are a couple of implicit cases of sexual intercourse, but these were appropriately edited. There are no bad words or drugs. The only big deal is moral dilemma, so I trust anyone over 13 would be perfectly fine watching this movie.
Warnings for the original manga fans: the entire college arc is skipped and the general story is severely reduced, cutting off a lot of the drama between Yori, Iku and Kusonogi.