As many reviewers have implied, there are two separate movies within "The Invention of Lying." I very much enjoyed the first one, the extremely imaginative comedy part. But, although the film buff in me wishes the director had stuck with that, as it would have made for a more consistent and unique movie, I did like the second, more serious, sensitive and honest part as well. And I am very impressed with Ricky Gervais. The movie is worth seeing.
I and my son were, for the most part, bored by this movie. It had a few semi-funny lines, but, overall, it was just weak and lazy. And the 3-D wasn't really used much at all. This is just a kids' movie at best.