Definition of "overblownness"

He was hooked immediately by the overheated imagery, the overblownness of it all. No writer he read had ever communicated that feeling of an incomprehensible madness.

2011, Jason Zinoman, Shock Value: How a Few Eccentric Outsiders Gave Us Nightmares, Conquered Hollywood, and Invented Modern Horror, New York, N.Y.: The Penguin Press, page 61