The Lego Movie is great fun, and I recommend it. Surprisingly, it sometimes manages to avoid the pitfalls of a product-placement movie for Lego products and concentrate on telling a good story. The script is good, the voice acting is good, the music (by Mark Mothersbaugh) is excellent—honestly worth the price of admission in its own right. It is highly implausible that this film should be rated PG instead of G, but there you are.
If The Lego Movie has a flaw, it is trying to pack too much into a short running time. The consequence is that the action is pretty much frenetic nonstop, and there are few opportunities for the kind of cinematic moment that the Lego video games excel in. The obligatory ominous shot-from-below of the enemy spaceship, for example, is so quick that the whole point is lost. All of this is especially sad in that [spoiler alert] most of the action is really irrelevant to the resolution of the film.
On the other hand, I cried at the end. So go see it. (B)