Michael Phillips called "Igor" unfunny, "uneven and overstuffed," although highlight the presence of Scamper. The "San Francisco Chronicle" writer Peter Hartlaub opined "the filmmakers waste some clever and subversive writing by cramming everything into a Disneyfied plot filled with misunderstandings and morality speeches." Similarly, "The Globe and Mail" thought its interesting monster movie concept was "thwarted by traditional prejudices." Wrote Kurt Loder, "the picture suffers from a humor deficit. The fact that the jar in which Brain resides is mislabeled "Brian" is not hilarious; nor is a strained butt-scratching gag involving an invisible talk-show host." The story is "innocuous and predictable—a modest do-gooder trying to pretend that its not Cartoonland's most direct attack of the Bush administration," wrote Amy Nicholson. In the opinion of an "IGN" critic, "Writer Chris McKenna [...] has essentially crafted a tale that robs the genre of all of its hallmarks – real monsters, gore, or even just genuinely scary moments – in lieu of a superficially entertaining tome that either borrows heavily from the above predecessors or doesn't have enough creativity not to steal from their iconic landscapes."