Where do I start? The plot of the movie, which is about a love between two high school students during wartime, while one is a living weapon, and their struggle to maintain that love is a very good plot. It is based on a manga by Shin Takahashi which was also turned into an anime in 2002, both of which I have yet to read or see.
This review is about this live action adaptation however. Sadly, this honest to goodness was a terrible movie. It isn't as if one could site certain aspects, and say, for instance, the budget is at fault, or the acting is to blame. It is, sadly, a series of underwhelming and ineffectual elements that bring this film down.
The acting is poor. Not to say Aki Maeda and Shunsuke Kubozuka are bad actors, but they didn't have much to work with, and seemed miscast. Neither seemed to have the physical range to draw the viewer in the story as well as being too old for their parts to a distracting degree.
The script was weak, the leads act unrealistically, and behave irrationally. The film also plays for the heartstrings, but ends up being predictable, all the while not being compelling, and under-developing the characters. There are also pacing issues.
Visually, it is unremarkable. The film uses green screen heavily and unnecessarily in too many scenes. The other special effects also have a cheap look to them, especially where minimalistic practical special effects could have been used. There is also no visual flair, as if there were no cinematographer or art designer to make the scenes look consistent and stimulating.
The music and sound effects were fine, but unremarkable.
Overall, the movie isn't devoid of enjoyment, and fans of the series shouldn't be discouraged to see it at least once just for the sake of completion. People unfamiliar with Saikano, this probably isn't the place to jump in as it isn't a very good movie or melodrama. It isn't the movie or the cast and crews fault, it just isn't inspired, and that is what kills it.