ALA Booklist (Sat Apr 01 00:00:00 CDT 2017)

Sixth-grade hamster-monitor Sam Gibbs and his affectionate, if predatory, charge really have to step up their game when Horace Hotwater Middle School is twice trashed by a towering megasquirrel ldly addicted, suspiciously enough, to the chemicals that flavor local junk food giant SmilesCorp's Funchos Flavor-Wedges. Worse yet, Hammie's being blamed for the destruction, and Sam has but a week to prove his furry friend's innocence before Hammie's consigned to the Irma Bergstrom Memorial Home for Troubled Small Pets. Following the trail of evidence leads to several startling revelations, notably inside SmilesCorp's secret animal-testing labs, and ultimately to a spectacular climactic clash of (temporarily) titanic rodents. With significant help from Kiefer "Beefer" Vanderkoff, the bully so thoroughly humiliated in the previous episode (Hamstersaurus Rex, 2016), and his beloved boa constrictor (kitted out with wings and feathers and, wait for it, a feathered boa), O'Donnell mixes a bit of reconciliation into this sequel's offbeat corporate satire. The occasional line drawings add appropriately daft visual notes.

Horn Book (Tue Aug 01 00:00:00 CDT 2017)

After Sam dubs the classroom pet Hamstersaurus Rex, it eats a strange protein powder and mutates into a tiny dinosaur-hamster hybrid; Sam teams up with "Hammie" to stop a bully. In Squirrel Kong, they prove another mutant framed Hammie for attacking the school. Amusing, Big Natestyle black-and-white spot art can't salvage this forgettable new series, filled with lackluster characters and hackneyed cartoon antics.

Kirkus Reviews

When the blame for monstrous destruction lands on Hamstersaurus Rex, Sam must clear his tiny, half-dino buddy's name.Bully Kiefer "Beefer" Vanderkoff has been expelled from Horace Hotwater Middle School, and as Hamster Monitor, Sam gets to care for his class pet: a mutated, junk-food-obsessed hamster/dinosaur hybrid. All's well…until the school is visited by rodential destruction on a mass scale and Hammie is the only possible culprit in everyone's eyes. Everyone, that is, except Sam, who, while filming Chinchillazilla vs. MechaChinchillazilla (starring Hammie, of course), is attacked by a 12-foot-tall squirrel. Sam discovers that someone is controlling Squirrel Kong (his money's on Beefer), and Sam has to prove it in order to save Hammie from being sent away to the Irma Bergstrom Memorial Home for Troubled Small Pets. When this seems impossible, Sam teams up with several former nemeses to expose the real culprit. Can he do it before a classmate tries to claim a $300 reward for information on Hammie's whereabouts or before Squirrel Kong destroys the whole town? O'Donnell's sequel to Hammie's eponymous first outing (2016) is as goofball as the first. Dotted with Miller's black-and-white cartoon illustrations—in which Sam is depicted as white, with classmates of various skin tones—it's sure to please those who enjoyed Hammie and Sam's first adventure. The "2" on the spine and the cliffhanger ending indicate more genetically modified fun to come—hurrah. (Science fiction. 8-12)

School Library Journal (Mon May 01 00:00:00 CDT 2017)

Gr 3-6The story of Sam Gibbs and the mutant classroom pet who acts as his sidekick continues. In this volume, Sam and Hamstersaurus Rex face off against a giant squirrel who appears to have ties to the shady SmilesCorp, which, in turn, seems to be linked to everything from Sam's school (especially one suspiciously cool teacher, Mr. Duderotti) to the Antique Doll Museum to Sam's mom (she works for SmilesCorp, and she's a very nice lady). O'Donnell includes even more jokes and action this time around and also cleverly reprises the most memorable characters, such as Hamster Monitor Martha Cherie and bully Kiefer "Beefer" Vanderkopf and his pet snake Michael Perkins. Sam's drawings are less prominent on this go-round, while O'Donnell's spoofs of adult behaviorincluding the maniacal, vengeful delusions of former SmilesCorp employee Roberta Fast and the latest lifestyle choices of the deeply sad Coach Weekesare funnier and more pointed than ever. Like Louis Sachar and Dav Pilkey, O'Donnell writes joyful silliness for readers with a budding adolescent sense of humor, and Squirrel Kong's absurdism may resonate even with grumpy, neurotic adults. VERDICT A pure blast of fun for readers who want something amusing and fast-paced.Abigail Garnett, Brooklyn Public Library