Almost unwatchable, especially for anyone who knows the anime or the manga. Sure, adaptation is not that easy, but when the source material is great, one could hope for something ... not that cheap, because here lies the problem here : Everything is cheap in this movie.
From the poor cast choice (while the acting is not really the problem here) to the actual filming, it lacks in every way, and we end up unable to get a good grip to the characters chemistry. Which is a real issue since the story focus especially on that point.
So, don't be surprise if you stop the movie midway because you're bored. That's perfectly fine.
I can only encourage you to watch it again from where you left by 10 min steps each time, then end this torture and actually forget it fast. Really fast.
Too bad, I was looking for this.