A major problem with What A Nightmare, Charlie Brown by Charles M. Schulz is that the format and illustrations suggest it was written for young children. The familiar and popular Snoopy and Charlie Brown are presented in full color, comic strip style. The small quantity of text does not form a cohesive or credible story. Basically, the "plot" concerns Snoopy's nightmare encounter with frightening monsters and terrifying dogs in Alaska following his overindulgence of pizza. The monsters in this book are consistently vicious and realistic and Snoopy only manages to save himself from them by magically becoming more vicious than they are. The whole thing seems purposeless, confusing, and somewhat frightening for small children. (p. 92)

Jean Marie Hiesberger and Pat McLaughlin, in New Catholic World, March/April, 1979.