So, first of all, I'm a big fan of creepy stories centered around kids restaurants and mascots (who are terrifying on their own), and I was interested to see what this piece offers. Well, there is some atmosphere and aesthetic here, but outside of that, the piece didn't hit me that much.
This feels like it has several cool ideas, but they're boiled down to tired cliches from horror literature and aren't explored any further. First of all, we are told immediately what the reason for the machines malfunctioning is, it's the missing children who supposedly died and got their souls transferred there (or something). This detail removes any mystery from the big chunk of the piece and makes it seem far less engaging than it could've been. It's pretty pointless to show us various hints and details about the children being there if you've already told us everything at the beginning.
The twist with Arcadia using children to produce an advanced AI is… Fine I suppose, but not that special considering the concept is hardly new or original. Outside of that, I don't see a realistic goal of this project: the problems caused by missing children and people finding a connection to Arcadia far outweigh the possibility of making some arcade machines better. Also, the fact that the Foundation was hurting the kids via playing seems to be thrown in there haphazardly to invoke more emotions, but it's not that big of a twist (again, because we know what's up with the arcane machines pretty much from the start) and isn't explored much further beyond the cryptic messages, which lose their effectiveness due to being shown so late into the article. Similar topics were done right before, take SCP-4361 for instance, in which the Foundation researcher realizes how it hurt the anomaly and how horribly she feels because of this.
I understand what the piece attempted to do, but due to its structure, it ended up feeling pretty uninteresting for the most part.