A high concept gets low execution in “Planet 51,” a lame-brained toon that even kids will recognize as an insipid goof on sci-fi conventions. Any number of things have been and could still be done ...

PLANET 51 would be a good film, if it was an original idea, wasn’t so long, and had a cast that wasn’t just going through the motions with zero confidence. Yes, it other words, PLANET 51 is not a very ...