After a second play through of Nier, I'm confident when I say that it may be one of the most underrated games of the PS3-X360 generation. To make a comparison, it's like Kingdom Hearts (combat, enemies), Shadow of the Colossus (terrain, appearance), and Final Fantasy (story, characters) rolled together.
The story itself is unusual at first, and the combat is a little repetitive, but after some time it becomes clear that this game is more about the whole experience than just any single element. There are numerous gameplay styles here, including brilliantly written text adventure-esque missions. Really, I felt like this was a game for older gamers, people who can appreciate all the styles of game's they've played before, now in one package. For example, in many games you'll find yourself in a cramped dungeon, and the game is locked to a 3rd person view, leaving you to say "This would be better if I had a top-down view". Here, the game designers chose the best way to approach each given situation, not to make it easier but to make it more enjoyable.
Another notable feature of this game is the multiple endings. The story itself stays the same, but how your perceive it is changed. By incorporating a few new pieces of information into subsequent play throughs, the entire mood and message of the story changes. What you saw the first time takes on a new meaning with just the addition of subtitles for the made-up languages, or a different perspective on the same battle. The replayability is very high.
There are two things worth complaining about. First, the side-quests have you running all over the place. The amount of time you spend traveling between areas isn't horrible thanks to your character's quick speed, but the fact that you'll be tasked with going right back to where you just were (or a place even farther out) gets old fast. Still, it affords you great grinding opportunities. The second complaint is minor, but in the US version of the game the main character is an aesthetic catastrophe. The dude is unpleasant to look at. I'm not trying to be shallow or anything, but in a world of soft, whimsical looking people, this guy clashes with it like a hammer that got dropped into a wedding cake.
Overall the game is enjoyable, inviting, and intriguing. It's definitely a collectable title just for it's uniqueness.