*A few possible spoilers ahead
First off have you seen that cover? Gorgeous. No wonder why I picked this book up in the first place. It also got quite a lot of love when it first came out so I had to read it. Did I read the same book as everyone else because I feel like I'm in the minority here when I say that this book and I didn't get along.
It all started when I realized that there was nothing mildly redeemable about the characters. There was no substance to any of the side characters, especially Luke and Sunshine. The main character is weird and not in the good way and to top it all off the love interest is a creep. The book was packed to the brim with instances of Violet blurting out the most random things and it almost never made sense, but none of the characters except for Luke seemed to notice that she didn't know how to hold a conversation and that she brought up irrelevant topics.
There was also absolutely no reason for Luke to be that nasty to his sister. I get it, siblings fight, but there wasn't a reason for Luke to hate on Violet. I kept waiting for some sort of childhood flashback to explain his hatred but there wasn't any. It was just there for the author's convenience and to show that the characters developed by the end. The same issue was present with Sunshine. She was written as a self-absorbed, bitchy girl but it's not like this added to the story, in fact it detracted from it because most of the time I just wanted to her go away.
The romance made me cringe. Their relationship developed unnaturally fast and I felt like I had no reason to root for them. The way River talked to Violet was very strange. If a guy started talking to me like that I would avoid that relationship at all costs. Occasionally Violet would start thinking logically about how dangerous River was, but then she would decide she didn't care because she felt in her heart that she should keep giving him chances and that he doesn't mean to kill people, even though he tells her that he does not think killing is morally wrong and that some people deserve to die. He also can't seem to stop lying and Violet is aware that everything that comes out of his mouth is a lie, yet she still chooses to believe what he says. If that's not alarming then I don't know what is.
The entire book felt like a jumble of literary and movie references that did very little to advance the plot. It also seemed like the author tried to mash too many gothic or horror story ideas into one book. The whole thing with Jack and the kids in the cemetery was very strange and it felt out of place. The villain of the story didn't even make much of an appearance until the end of the book. I saw a few people talking about how great the twist was at the end of the book, but I knew what the twist was since the mention of siblings and Texas.
Between the Devil and the Deep Blue Sea was a major disappointment because it had so much potential, but it was executed poorly.