If you watched this expecting your normal fluffy anime pap, then no wonder you didn't like it. It was a beautiful portrail of a side of war that often gets overlooked, an examination of a society that is breaking down under the stress of WWII, and a cathartic story told by a man still eaten away by guilt at the real death of his sister during that time.
There is a reason that the movie has been compared to such powerhouse films as Schindler's List and has routinely been given glowing reviews by critics. It is the most emotionally charged and powerful anime I've ever seen.