Spoilerly, my one real complaint here is about the pacing of the end. The climactic "grandma is back" dinner scene with Sam, Phil, and Sam's mom Edith is perfect and is everything I wanted out of this book. In the author's note at the end, it says that this is the crystalizing scene that the rest of the book was formed around and I can see it.

During this scene, Gran Mae lashes out at everybody, but Sam finally stands up for herself. But then, Gail just walks in with some weed killer and concludes the whole thing. Gran Mae goes "oh you don't want me here? well I'll just leave then, hope you like the underground children I've been protecting you from! byeeeeee". The "big bad" of Gran Mae is easily dismissed, as if any meddlesome racist grandma would ever leave because they were merely unwanted.

At that point, everything goes to hell (almost literally). It's not that the underground children weren't well telegraphed, but it feels like a bait and switch of the source of tension. It goes from subtle creepy family horror to homunculi are attacking us in an eldritch dimension action horror. And, for me at least, this is a much less interesting horror flavor.

And, while we're visiting spoiler town, I wanted to say that I appreciated that the story took some time to detail why Gran Mae acted the way she did. There was a reason she was deeply focused on keeping things normal. There's also no excuse for this; it's not a "hey let's sympathize with the villain of this story" moment, but it does create some added depth that makes her awfulness more believable.