Finished it yesterday for the A ending and today again for the B ending (then watched C and D on youtube, not into the whole weapon collection and save deletion thing).
I was left completely in awe by this game, it for me is one of the best games ever made.
The visuals were fantastic and the architecture was excellent, extremely memorable locations and world for me. The soundtrack was beautiful, haven't been taken this aback by a soundtrack since SOTC, so many epic and tragic tracks, just holy shit.
The characters and story really kept me going, even the side characters (like the Masked people) were very well presented and designed. Really felt for the leads. The story was amazing, didn't expect it to be this good. The B ending run made me adore/feel it even more.
The game reeked of Team Ico I think, especially in terms of the environments (even the way Nier ran), not to mention the Shades. Ico also did the whole translation of the language that you can't understand on another run iirc. I take all this as a positive, of course. Team Ico like visuals + deep story and characters + violence made for one heck of a combination.
The gameplay was really fast and fun, the powers were cool and I liked how they were useful throughout the game (I was using the very first ones I got often till the end of the game). Ignored the quests for the most part so the gameplay was pretty much completely frustration free for me. Not a fan of long games but I seriously didn't want this game to end :/
Overall, I give it a 20 out of 10.