Well for the story for Casshern Sins it would best to say that the show starts off on a good note and becomes gets fairly interesting, but then by the end you really wonder what it was all about. To go into more detail it is as I said it starts out to be very interesting with the creators laying out an apocalyptic wasteland with everthing falling apart including a majority of the worlds citizens. So for what reason is everything falling apart well that would be because the shows leading role Casshern killed the one called Luna and as a result the entire world is falling to ruin and of course our lonely hero is the only one unaffected by the ruin and can't remember anything about anything. Does it sound interesting? Sure. Would it have made for a rather good anime? Sure. But did it? No. So why might that this anime that should have had a good story fall short. Well that would be because despite starting out good the main plot is for the most part completely abandoned until the last couple of episodes and in it's place we are left with a story that for each episode we get a new focus that is for the most part completely forgotten come the next episode. Though of course that being said the one-shot episodes is actually where Casshern Sins is strongest in terms of story. I for the most part would have been a lot happier with the story if it had either gone completely with the one-shot episodes instead of trying to squeeze some kind of main plot into the overall story or if it had stayed with one larger plot instead of several one-shot episodes.
The animation is in fact where Casshern Sins does a rather fantastic job. The color schemes in addition to the superb animation create a visually pleasing sight combine that with some excellent lighting and the in the animation in Casshern Sins is extremely well done.
As for the sound it did well in some departments, but in other areas it fell short. The voice acting was not the best I had ever heard with the main character always seeming to lack any emotions whatsoever. Though I will admit that some of the supporting characters do fairly good jobs most of them tend to fall short. As for the background music it was overall very well done with the musical scores doing a excellent job in blending with the atmosphere that the series was trying to create.
The characters well it's pretty sad when the main character of a series is easily not the most interesting character of the group or even that well developed. Which is exactly what we get with Casshern and so in addition to the bad voice acting we also get a main character who for the most part doesn't undergo any real change from the start of the series to the end of the series. As for the main protaganist of the series Dio and Leda was pretty much as bad as Casshern. Nothing about them gets explained in the slightes bit. Though I will say that the most interesting character Lluyze, but it really was a shame that she only got one real episode dedicated to her.
Overall while I did find myself somewhat enjoying Casshern Sins. It might be best for someone to say only watch a couple episodes at a time instead of the whole thing in a short period of time because they could find themselves tiring of it rather quickly.