It's the love child of Zelda and Drakengard. It's Cavia's best game yet. Welcome to Nier.
The Legend of Zelda. Yep! For all it's heavy Cavia flavor, this game borrows a lot from Zelda, and even gives some obvious nods to that series. Nier is a fresh new take on the Zelda formula. You could almost call it "Zelda for grown-ups".
Without giving away any plot elements, you can expect lots of hack n' slash with large, unwieldy weapons, sometimes with a similar feel to Monster Hunter, some very well implemented magic abilities, extremely varied gameplay ranging from unique camera view changes to a sequence that is basically a text adventure. Cavia has pulled out all the stops to keep things utterly interesting from beginning to end in this epic adventure. I myself can't wait to start my next session with this game. If you're feeling like RPGs have been a little derivitave/boring/tedious lately, Nier will feel like a breath of fresh air.
There's little more to be said. Go play Nier.