The general idea was much more interesting than I was expecting, so much so that I'm willing to give this movie a tepid favourable recommendation. I found the dialogue, the direction, and especially the acting to be weak. Not one of Matt Damon's better performances, nor was his supporting cast helping out much.
The movie has the feel of a made-for-TV movie (although I can't pinpoint why), but the story itself was interesting, and Emma and Steve both deliver good performances. The movie won't blow your mind, but it's a worthwhile watch nonetheless.
I've watched a lot of children's movies lately, and this one was the worst. It's terrible animation, arguably the worst voice-work I've heard (at least the english version), but I do need to say, my 4-year old didn't mind it, so MAYBE it's not quite as bad as I thought. But it's impossible to say that it's "good".