Watched Planet 51 last night and I have to say I'm a little dissapointed.
While it's a gorgeous looking movie, all things considered, it's the plot that hurts the movie overall.
Feels like it was recycled with bits and pieces of much better of much better sci-fi films that are shamelesly put into(the Star Wars references are so obvious I wonder why Lucasfilm didn't sue). The characters aren't all that great either, good performance overall from Dwayne Johnson as one of the lead protagonists and OK performances by Jessica Biel, Sean William Scott and the always charming John Cleese. But, how should I put it, the film carries no emotional weight on this, even a kid watching this might not feel anything for any of the protagonists or even care.
The jokes in this flick are too over-the-top and some odd ones and probably too adult for kids to understand or take it the wrong way.
I give it a D.