What makes this writing bad?

Dan Brown, author of the Christian-bashing, made-up-history-presented-as-truth, mega-selling novel The Da Vinci Code has a new book out, The Lost Symbol. This time the conspiracy has to do with Masons and Washington, D.C., as well as the Catholic church. Critics are lampooning the thing, but that surely won’t prevent millions of people from reading it and believing what they read. This British article cites some of the criticism and proposes the author’s 20 worst sentences. Read them, but first let’s test your literary discernment. What are some things that are wrong with this passage from The Da Vinci Code, chapter 4?

A voice spoke, chillingly close. “Do not move.” On his hands and knees, the curator froze, turning his head slowly. Only fifteen feet away, outside the sealed gate, the mountainous silhouette of his attacker stared through the iron bars. He was broad and tall, with ghost-pale skin and thinning white hair. His irises were pink with dark red pupils.