Preliminary thoughts about 46% of the way through. I dislike the false solution that Munakata thinks Yuki was the executioner and committed suicide by ingesting too much salt/miso/soy sauce in the virtual world. It feels really weak. I can buy him being lazy enough to not check dust on the bookshelves and that disproving his false solution, but the salt overdose as poison feels much weaker/less likely and something that should more be verified.
That said, I liked the doorknob knife trap he set to catch Kamo, and it was funny seeing him lie on the bed while others did work/investigated. And the way he cares for his dog, who was taken hostage, is honestly pretty humanizing. I loved the moment he was like "I wish I just left him on the street...so that he wouldn't be a hostage now."
Overall, not great so far, but it's okay. Diagrams for the bookshelf/boat locked room helped, but I'm not in love with the piece. Hard to say why or why not...maybe it's a little too complex and some parts go over my head. There's also so much swapping in and out of the virtual world. Eh, I guess it just feels strange and different from other mysteries.
Edit: can't say I like the dollhouse/puppet house trick even with clues like the poison dosage being scaled down specifically and the in game units changing/going missing. If the gamemaster is just gonna spawn them in an identical miniature model of the previous building, there's no limit to the BS they can spawn to assist the murderer. Will continue though.
Edit again: I'm close to the finale. I figured there was something with an action in VR actually happening in real life, but my suspicion was far more sinister. I thought one of the people would be induced to murder in VR but in reality commit it in real life without realizing. Can't say I love the trick of disconnecting the machine and the same actions replicated in real life, but it's fine. I don't think it's a bad idea at least, and it uses the premise and setting well. My main issue is needing to know that the nut bolt put onto the body suit disconnects them from the VR machine's hole. It probably was stated in the description of the machine, but we definitely were not shown a person disconnecting physically from the machine. But I think this is probably a nitpick of mine, and I still consider it fair.
My favorite aspect so far is Kamo using his role as VR murderer to eliminate one of his two suspects (Kenzan), thereby giving that person an alibi, in order to narrow the range of who could be the executioner to just Azuma. It's rare that a character who is a murderer can use their role like that, actually intentionally giving someone an alibi to eliminate possibilities, and I love it. I also loved the ending reveal that the mastermind Chikage/Azuma is actually Kamo/the protagonist's lover from his original timeline, before he changed history in the first book or so. I love that idea of destiny because it's so romantic - a lover from another "What if" timeline and the hidden connection meaning that she was able to be convinced by Kamo. Of course, there's an air of tragedy about it all as Kamo/Chikage don't know and don't connect in this timeline, plus Chikage's background is rough with how the amateur detectives caused so many tragedies for her family due to their incompetence. But it was still an emotional reveal.
Then there was the reveal how her husband, the detective, was actually very capable and found her crimes...only to cover them up for her. I liked that a lot as well, choosing his wife/love over his job as a detective/justice even if she was a criminal. And of course, there's the tragedy with how she chose to kill him for it, yet you can tell how much she regrets it.
But it's ironic, my favorite aspects of this book actually are NOT related to the core mystery itself, which is solid and fair play enough, but I didn't love. The tiny-large house shrinkage wasn't a trick I liked, then the other tricks like creating a vacuum space and using air in the boat to hold back the door were fine, but I don't know why I didn't love them. I usually like scientific tricks, but I think the combination with the VR aspects made it harder to follow and less enjoyable. It was the motive, the reveals with the murderer, and the tragic air around the end that I enjoyed most.
But anyway, overall, it was still solid. More fair play than a lot of English mysteries I know at least. Overall solid, and I think I'd enjoy this more if I actually read the first two in the series. I will probably read them eventually.
This entire review has been hidden because of spoilers.