This "film," and I use that term loosely, reminds me of the first joke my daughter wrote, at eighteen months: "P.U., stinky poopies!"
Like that joke, this movie can only appeal to the very young, the very immature, or the very stupid.
That said, there are a few bright spots.
The effects, where the majority of the reputed $100 million went, are kinetic and convincing -- I mean, as convincing as those kind of kinetic CGI effects can be. The CGI baby effects are not great, but I imagine those are very hard to do well... although for a hundred-million bucks, they could have been better!
Moose, the dog from "Frasier," phoned in his usual exemplary performance. Steven Wright did well with a small part. Alan Cummings was, well, Alan Cummings-as-villain, which we've seen before, and Bob Hoskins as Odin was unrecognizable, but enjoyable.
The actress playing Mrs. Avery was cute-as-a-button, as you'd expect, and Jamie Kennedy stunk, as you'd expect. His best role so far was in the Scream trilogy (not to be confused with the Lord of the Rings trilogy), and in Three Kings. He should stick, perhaps, to more subtle forms of comedy. Jim Carrey, he ain't.
The writing and direction were, if anything, worse than Kennedy's performance. I semi-remember one clever (though seven-year-old clever) line that I wish someone would quote accurately for the "Memorable Quotes" section. Something about Avery's proposed costume being the "crappiest crap in Craptown," it was a second-grade joke, but sort of funny in context.
Over all, since there's nothing lower than a "one," I give this film a "one."