This is an unbelievable anime. My first impression was that the quality looks sounds and the characters cute and interesting. I didn't expect that, even though this is true, it was so deep. If you want or anticipate an easy anime that puts that smile on your face and maintains your interest, or if you are faint of heart, I advise not watching this. It isn't "easy" on the heart at all but wow, the ride was worth it (finished it on 5/06 in a day, it was that good).
As I said before, brief inspection highlights what is true: it is a beautifully styled anime. Watching it was stunning, especially when multiple motives were effectively used. The soundtrack is phenomenal and brings the atmosphere and depth of the anime from the start.
I loved it and am still in awe at the depth, multiple levels of meaning, symbolism etc. This did mean that it did make the anime feel saturated as I'm forced to just sit passively along, waiting for the mind to catch up at the new landscape and world. The characters are awesome, but suffer similarly as the story line. However, by all means, it is still considerably better handled than most.
Seriously, if I were able to comprehend everything at once (impossible if you just delve in as I did without knowledge of all the background stuff to full appreciate the awesomeness) then it would be full marks; I'm practically researching all the intricacies of the anime months after.
Naturally, I want more!