Ironically, should NOT have been written by the game's writer.
First and for most, I liked the movie. It was something that I've been wanting since first played it back in 04. With that said, this movie had no depth whatsoever, and I believe it's because the writer has been with it for too long. He was telling the story as if everyone already knew it. This isn't a fairy tale!
I was able to follow along because I knew the story - I've had 12 years experience with the franchise. I saw it with my friend who hadn't, and she didn't care for it too much. I shouldn't of had to spend an hour explaining everything. (Was there a reason why the bit about why the Blarg needed a new planet wasn't in the movie - it would've added what - 30 seconds?)
Sure, the game is for fans, but why? Why was it only for fans when we're just gonna play the game and got a much deeper experience anyway? I thought the movie was to introduce Ratchet and Clank to the world?
Sorry to say, but they could've lifted the original 2002 story word for word and movie-goers would have had a more complete experience.
At least they didn't loose too much money. The movie is so tied in with the game, ticket sales are probably pure profit.