I think that this four part anime would have benefited greatly from having an additional 2-4 episodes. This small addition would have allowed for more substantial character development and plot cohesiveness.
The animation, for the most part, fit the mood. . . dark and depressing. However, it was a bit off putting to me that the "love" interest Shou Yaegashi looked almost exactly like the main character Kazuna Takashiro.
The sound effects were sometimes a distraction from the show itself. . . (example episode 2) I do, however, feel the ending song was a nice fit.
The characters had real potential, and just as we were beginning to scratch the surface. . . the show came to it's abrupt and disappointingly predictable conclusion.