NieR is easily one of the most beautiful and heartbreaking pieces of storytelling I have ever seen in a video game. It has a dark and gritty world with a very sinister sense of humour and, whilst it doesn't reveal very much until the very end, it's filled with twists, especially if you play it more than once. By the end of my second playthrough I was in awe of what it had put me through; I felt really, REALLY despicable for the role the game had thrust me into. We were lucky enough to get the Gestalt version instead of the Replicant version localized, which I think adds so much more depth to the protagonist; a father out to save his daughter is a lot more scarce than a sibling relationship. The cast outside of that is also fantastic and unique, and has a weird sort of chemistry that makes for a very entertaining tale...despite the gritty and constantly depressing atmosphere.
...it also has the greatest video game soundtrack in existence. That is perhaps the only thing about it that ISN'T underrated - a lot of well-deserved praise has gone towards the OST, but the game itself is constantly criticized by people who clearly didn't play beyond the first ten minutes. It has a spectacular story and cast that is well worth experiencing.
