For what is essentially and hour-long anime, it really packs a lot in there. Lots of bloody violence which is nicely balanced with the more emotional side of things (plus some nudity to add to the dimension of things). I felt the plot moved at a nice even rate and I didn't feel bored at any point.
Animation: Well, for a 10 year-old anime is was very well animated. Everything looked smooth and sharp and the slightly more 'old-skool' style simply added to the grittiness of the content. The fight scenes were one of the highlights as the choreography was really well done and really got you into the scene.
Sound: Does exactly what it says on the tin. No particularly memorable themes or anything but the sound effects were exactly as you would expect.
Character: Without giving too much away. The characters developed well over the course of the anime and you empathise with the main characters and end up disgusted by the way some of the others treat them in such a way that you expect the director was aiming for. A definite plus.
Enjoyment: As you would expect I enjoyed it quite a bite due to the reasons mentioned above and I wouldn't be against possibly watching it again.
Overall, I would have to say that if you're looking for some proper hentai then look elsewhere, but if you want to see a good piece of quality anime then this is something I'd recommend :) .
