Shining Girls, not a novel about the twins in the Stephen King horror story

I read Lauren Burkett's The Shining Girls in about a week.Well, a year and a week, because first, I checked it out from the library and didn't finish it, and then I recently found a paperback version for sale at the same library for $2 and so bought it,

Do you know about this book? Writer Tana French has endorsed the novel, but I don't necessarily trust her judgment anymore, not after reading The Secret Place, which was a really long literary version of Dawson's Creek without the intrigue or multidimensional characters.

The Shining Girls does this odd thing where it straddles two to three genres at one time. It's an historical book about a serial killer who time travels to find and murder his victims, women he sees as" shining;" meaning that they are particularly vibrant and strong, not your typical victim. He doesn't just kill them, he dissembles them, pulling out their intestines and doing the killing slowly, because it turns him on.The heroine is one of the victims who survived, and who gradually figures out that he has this magical house he can go into to move among the decades and get away with his crimes.

I don't know. I found it to be confusing--particularly the ending which, granted, I sped through at 10:45 p.m. and so perhaps didn't read carefully enough. I think what happened was that somehow, the bad guy was killed in a certain time period and so perhaps the other crimes never happened? Or else the bad guy was killed but the bad things will still happen in exactly the same order. I also read the author's interview in the back of the book where she explains that she wrote the book to give the victims a voice because she knew a girl once who was locked in a house by her boyfriend and died in there. I don't think the characters here had much of a voice, since all of them died and only one escaped and then she kind of gets saved at the end by a guy. But I think mostly I feel stupid for not understanding the finale.