I agree with all of the points made in the other reviews. I enjoyed this anime for the fight scenes and the depth. The fight scenes, as everyone says, are incredible. Fast paced, complicated and well animated, they keep you watching. The credits during the opening became a bit tedious during the last few since they interrupt the aerial combat which CAN be tricky to keep track of. However the remainder of the fight scenes are great.
It is important to note, however, that any comments you find about lack of narrative are absolutely true. There is no explanation of ANYTHING that is happening, not from any of the characters who have such knowledge nor any dramatic narrator. This is something I actually enjoyed about the story. During the first ten minutes I was blown away and completely oblivious as to the REASON why what was happening, was happening. However, this is a story where one can piece together the various elements through watching the story. This isn't to say, treat it like a detective story, but rather to say, while watching, you will see characters do or say certain things that make you think "I think he is this kind of character and this is his backstory etc..." Your experience with other movies, anime, and science fiction will guide your intuition. Put simply, the narration is non-existent, so you create it. I enjoyed watching this story and talking with my friends about who was who and what their goal was. The depth is present because the lack of narration allows you to wonder at the reality of the situation. Bit by bit the questions of who, where, when, why, and how are all answered, but while you watch there is an alluring freedom to the lack of explanation. By leaving the story up in the air, it draws you in with the tantalizing possibilities it suggests. In the first few minutes you are presented with the presence of transforming warriors with incredible powers, a seemingly normal girl with abnormal importance, and a police detective who seems to know more than most. The amazing story that this world COULD become drew me in like a terrible crime with no apparent motive. Why are they fighting, why is she important, what is the detectives connection to anything? I watched and continue to watch this story to attempt to answer these questions, and thus far the answers have not dissapointed me, nor the creation of more questions. I highly recommend this Anime to anyone interested in fantasy or science fiction despite the requirement of patience.