Before the genesis of this collection, I didn't realize that addiction horror was a thing. Now it makes all the sense in the world. One of the best things I've discovered through reading more independent horror is my own expanded definition of what horror means, what it can be. 
There are stories in this anthology like that of Gabino or John Taff that fit a little more neatly under the horror umbrella, with other-worldly creatures. Other stories like that of Caroline Kepnes and Mercedes Yardley approach it from a more human perspective and read almost as literary drama. Yet all display elements of horror and give us complex characters dealing with real fear. 
All the stories contained within are in novella/novelette form, and it ends up being one of the biggest strengths. As much as, if not more, than other forms of horror the reader must get to know the characters in order to empathize with their plight and truly take part in the horror that surrounds them. The longer form helps every story accomplish this feat and is a tremendous argument in favor of quality over quantity. 
Kealan Patrick Burke's Now They See Me is a bleak, beautiful opening. It's deeply entrenched in the style you know you're going to be reading. Pure Burke. 
Monsters was my introduction to Caroline Kepnes. This story is written in a multiple POV style that draws the reader in. This one draws from the evil contained within the human heart and leaves us to contemplate the god-awful things we do to each other. 
Lizard was a stand-out story written by Mark Matthews, who also edited the anthology. Matthews sets up in the introduction his personal history with addiction, both as an insider and an outsider. It is quickly clear to the reader that he draws deeply to paint the most true-to-life picture possible. The end result is a story that is tough to read at multiple points, but holds the anthology together. 
John F.D. Taff's The Melting Point of Meat reads with a tinge of Clive Barker, namely the last ten pages or so. It's a brutal exploration of a type of addiction we might not anticipate, but might be most likely to see day-to-day. It also serves as the King of Pain's foray into cosmic horror and has me all kinds of excited for a potential collection of cosmic novellas from him. 
Gabino Iglesias contributes Beyond the Reef which I found to be one of the strongest entries. The opening salvo comparing addiction to parenting is passionately written and poignant and roped me in immediately. The remainder is creepy as hell and has a fun Lovecraft connection. 
Love is a Crematorium by Mercedes M. Yardley was my personal favorite addition to Lullabies. Watching Joy's character arc primarily through the eyes of Kelly is heart wrenching, and while none of the stories here would be described as light and fun, this was the one that cut the deepest. Well-written and expertly conceived.