I'd say that one of my biggest fears in life is ending up with dementia. I've had to deal with a lot of stress and overload in the past decade that has taken a noticeable toll on my ability to remember things. I forget names and faces in a way that I never did before, some of my extended family (cousins, aunts, uncles) are just gone at this point. Worse still is that I notice it happening, which has made me consider if not knowing I used to remember things better would be sweet release. If I ended up with severe dementia, would not being able to recognise the people I love be blissful ignorance of the problem, or would it be a fate worse than death? It's a situation I hate to think about.
I haven't read any spoiler-filled assessments of the game's themes yet, so I might be off-base, but NieR: Automata, to me, is a game about this question. It's a game about memory, and specifically, its degradation and loss. From the very opening, it's clear that 2B and 9S place the utmost value in their memories. Their bodies are disposable, and it's the memories that define them. The A ending highlights this further by having 9S transfer his memories to the machine network and become one of them. He's still 9S, but he's no longer a 9S. But this also means that the loss of memories is the loss of the person.
The Wandering Couple sidequest ends with a dark revelation. In a pseudo-suicide pact, they agree to both be wiped clean to forget all their hardships and live in ignorance, but trusting to fate that they will again fall in love and be together. The husband goes first, but the wife refrains, revealing they'd been through this many times before, and that she always clears his memories while retaining her own, because he's easier to manage when he can't remember the bad times.
In the C playthrough, Pascal sees his village destroyed and all the children kill themselves. He asks you to either make him forget or kill him, to rid him of the heartache. While on the surface this seemed like a simple request to make the pain stop, the deeper question is really "is it better to lose all your memories than it is to die?". For me, this was a rough choice. Yes, Pascal is better off without the trauma, but is he better off without his good memories? Is he still even Pascal after that? I don't know, but I wiped him because I selfishly didn't have the heart to let him go. Later, I found him stood among the corpses of his dead friends, blissfully unaware, and selling off the children's cores for a quick buck. He was happy, but he couldn't remember anyone he cared for. I was crushed.
When the endings rolled around, it hammered home the futility of YoRHa's existence. Reliving the same things over and over while getting your memories erased at the end each time. Everything ultimately being meaningless, and that final gut-punch comes where I find myself asking "what is the point in life if you can't remember it?"
And then the game turns into an arcade shooter. A distraction. A toy that explodes with sound and light to entertain. Forget that existential question, here's a game to play to make you have fun. That's why you're here, right? That's what you've been doing these past 30 hours? Look at all these encouraging messages! You can do it! You're enjoying yourself now. Isn't that all that matters?
I deleted my save.
What a lot of shite the beginning of it is, can't be arsed with that.
: do the first few main missions until you unlock fast travel.