Clifford's Really Big Movie is a mildly amusing children's film without great aspirations. Despite its lack of ambition, the film has some admirable qualities-chief among them its appropriateness for the target audience and the built-in charm of an already beloved big red dog.
Some children's movies transcend their intended audience and become instant classics. Pixar's astounding run of hits comes to mind, with the Toy Story movies and Finding Nemo as shining examples.
Other kids' films, like the G-rated Clifford, may not achieve this same greatness, but are still effective and diverting entertainment for young children.
Don't make the mistake of thinking that adults or older kids will relish sitting through Clifford, even at the film's short 73-minute running time. On the other hand, toddlers and younger kids are likely to be fully invested in Clifford's flight from home (based on the mistaken assumption that his family can't afford all of the food he eats) at the very start, and won't rest easy until he is safely returned to owner and friend Emily Elizabeth at the film's conclusion. (Under other circumstances, that might be called a "spoiler"; in this case, it's a given.)
Admiring a film for its age-appropriate charm is not an argument for mediocrity. There's a strong-and harmful-tendency among reviewers to require a children's film to exhibit an adult level of cynicism or "sophistication" before acknowledging it as worthwhile entertainment. While Clifford may not approach transcendence, it is suitably "unsophisticated" enough to entertain kids and satisfy discerning parents.