I don't even know where to start with this game.
I loved the world, the unique setting, the incredible soundtrack (it's probably in my top10) and most of all, the characters. Nier, Kainé, Emil and Weiss make for a god-tier cast, each with their own nuanced quirks, and they fit together extremely well. The gameplay also has a very unique concept: merging character-action mechanics (à la devil may cry) with bullet hell elements.
This works only in part: in the end the result is pretty imbalanced, and the game starts to get too easy when you are 25% through it.
What really holds this game back is the absurd level of patience it requires to get to the end. You see, this game has a pretty unsatisfying ending, with a "big reveal" that creates more questions than answers, and a promise to give you a more fulfilling experience if you replay it.
Then you have to do a second playthrough of the second half of the game (which will take about 5 hours). The game was already too easy, and it doesn't have Ng+ scaling, so you are NOT going to be challenged. You are going to be annoyed and bored, but what keeps you going is new small tidbits of information, and the new perspective you have on the story, thanks to your knowledge of the final "big reveal". Then you get another ending, and the game asks you to REPLAY IT AGAIN, collecting all the weapons, which requires some FARMING.
If you choose to do so, you will be bored out of your mind, as you speed through content you already know like the back of your hand, just for a measly amount of new content at the very end. Good content, mind you, but simply not worth the hassle. By the way, you have to play the final act twice to get endings C and D
Then guess what? You have to replay the first half of the game, from scratch, to get a new final chapter. This is an incredibly stupid design choice, and it kind of ruins the whole game. Yes, I really enjoyed the parts I enjoyed, but most of my experience was just mindless, boring button mashing and dialogue-skipping. I feel that the whole third playthrough could have been cut and merged with the second, and the "ending E" section could have easily been put right after ending D, without having to replay the first act of the base game.
Furthermore, the base content is already kind of stale and uninteresting the first time through, with the most cookie-cutter, unimaginative sidequests I have ever seen. I have seen people claim that "that's the point", the director is making fun of you for going through all of them, and he purposely created some mind-boggingly long and annoying sidequests with NO REWARD, just to drive this point home.
This kind of falls flat, though: Taro hasn't earned the right to mock bad sidequests, since he has shown that he can't make a good one to begin with. You don't get to make a 2/10 sidequest as a fourth-wall-breaking metacommentary joke, when your best work in sidequest design is a 6/10 at best.
Overall, this is a crusty-old, stale, boring and unsatisfying mess of a game, with nuggets of true genius sprinkled in it. I'm still glad that this game exists, since it laid down the groundwork for Automata, where the concept truly reached its full potential, multiple playthroughs and all. I would not, however, recommend this game to anyone. And if I did, I would tell them to just get to ending A, and get the rest of the info from YouTube videos.