NieR is a game with a very interesting method of storytelling, it requires you to play the game multiple times to unlock the story and the truth behind it, which is very neat.
The story also contains reference to philosophical question albeit it doesnt dig deep enough like you would expect from other mediums it still feels satisfying enough to give the game some depth.
The gameplay however gets boring, the second playthrough with 9S gets repetitive and boring because of the shallow hacking minigames, and the open world itself doesn't help the game in anyway, the side content/quests you do are simple fetch quests that barely hold any value.

But overall, NieR is a great game that is worth playing. It's music and storytelling methods are worth experiencing.