I can just see Chris Ewan, thrashing around for months, trying to get the odd structure of this novel to work.
"Okay, I'm only limiting myself to scenes (Sections, and chapters) that take place on October 31st - in fact, there will be no locale changes either; always on the Isle of Man...but that's not really the problem. The problem is only showing what is happening to Claire, her family, friends, and enemies - including one deadly enemy lurking in the shadows (or among the friends, as far as the reader may wonder) - only on a bunch of Octobers 31st (October 31sts?), Hop-tu-naa (Isle of Man version of Halloween, um, expect rain).
"So, if I'm jumping, every time, right to the anniversary of the day a dare went horribly wrong for plucky Claire and her slowly dwindling group of pals (see successive 31sts), then how do I maintain any kind of forward momentum? Or rather, can the reader handle a sort of herky-jerky momentum? Details of a cursed, deadly day...and then another leap forward (a few helpful leaps back, in the early-going; also, skipping some years, in the early-going - until we focus on Oct. 31, 2011-2014).
"Here are the problems: (a) It's not like Claire loses at Scrabble every Hop-tu-naa and shrugs; serious lethal shit is scheduled, and Claire and her hexed friends come to fear the day. So, what about the consequences? I will not be showing them in real-time; I will constantly having to bring the reader up to speed - and make it have emotional impact, and keep the reader caring about Claire - when it comes to how the previous 364 days affected her, after that Halloween's terror and death. But I can't do too much "catching up with consequences, and detailing what's different a year later" or the Sections just become full of that - full of backing-up - and then there really is a momentum problem! Must move forward...but when jumping ahead again to the night of the living nightmares, the night of the action - but also must not just scar Claire and go right to the next round of scarring (oh, for the year when Claire figures stuff out and goes on the offensive...wait for it...).
"Problems (b) through (aa): what have the police been doing? why don't Claire and Co. (assume Co. shrinkage thanks to killer) break certain patterns, including moving off the island? how do I hide my murderer, year after year, with a shrinking suspect pool? what has happened, as of every October 31st, to all supporting characters - like: job changes, romance fizzle or fireworks, family dynamics, and how many paragraphs can I dedicate to that while I'm really gearing up for a killer Halloween that tops the last one?"
Inherent structural problems are not fully conquered, and the forward momentum is, at times "hurry up! ...oh wait, we have to back up a sec". It's hard to describe, and the author should get serious credit for sticking like a leech to October 31st for real-time scenes. I might also submit that he is not running the greatest Mystery in the history of whodunit. I certainly did not have the top of my brain sizzled and blown off by the reveal; "hm, okay, well, it had to be someone whose been creepin' around Claire all this time, and some tricks kept me from seeing which creep to pick. Yah. Fine."
But the book is suspenseful and scary; it is tense most of the way through, even allowing for the "how I spent my other 364 days, when someone hadn't scheduled my death or the death of one of my friends" recaps that suddenly pop up. They are necessary, and they do give the novel its...well, its story. I mean, the author knows better than to just drop us in the shit every Halloween at Claire's place. You need a story, even if the novel's must-be-that-way structure is snarling and spitting and throwing monkey wrenches at good friend Momentum the whole time.
Chris Ewan..finds a way. Let's not do this all the time, though. And my favorite book by him is still The Good Thief's Guide To Paris. Very different, of course (you get more than one day per year, for starters).