I can't rate this book decently because of the transphobic nature of one of the stories. Even without that, this is definitely weaker of Horowitz horror stories. A lot of them are worse re-hasing of stories he has already written.

The Man Who Killed Darren Shan: 3/5 stars for taking out the competition.
Bet Your Life: 0/5 stars for Transphobia. I don't know what it says when a character wanting to transition is replaced by wanting to help donkeys in the re-released. This story also has an unchallenged Ableism.
You Have Arrived: 2.5/5 stars for Dionaea Muscipula.
The Cobra: 2/5 stars for Spare Parts.
Transmission: Not really a story, just an excuse for a poem and a questionable fake letter.
Bad Dream: A poem about the mud coming for revenge for the father's sins. 2/5 stars.
'Why Horror has No Place in Children's Place by Wendy Grooling'-Here's a quote about J.K. Rowling 'It's all too often forgot that she has single-handly taught an entire generation the value of reading,' This is meant to be a joke (I think), but I wouldn't be surprised if that the coolaid that Just Kidding is drinking now, especially when she has the gull to imply that Autistic people are too confused to know their own genders. Even as a former HP fan, I liked books before I had read a single word she had ever written. How odd that ended up reading this book this week.
Horrorword: A crossword which is problematic and kinda bad anyway as a crossword.
My Bloody French Exchange: 3/5 stars for the same twist and I'm gonna straight-up reference it.
SheBay: 1/5 stars because Human trafficking online is definitely real and horrifying.
Are you sitting Comfortably?: 3/5 stars for life insurance.
Plugged In: 4/5 stars for Not Trusting Your Neighbours.
Power: 2/5 stars for extreme sports.
Seven Cuts: 1/5 stars for not respecting women

Proper review here.