I'm a well read grad student who's bluntly honest about all things, although I try to be most honest about myself.
If Rocket were swearing, or blowing more, ah, people up, this would be a five star rated book. But the problem with writing children's books of adult things is that you have to water down some characters, at least when you're dealign with the likes of Rocket and Deadpool. (Yes, I've seen a Spider-Man and Deadpool comic for kids...)
Overall, the author really nailed everything, he was just help back by this being a children's book. So I highly enjoyed it, but can't say that I felt it was five star due to the warping of the characters due to children.
Children ruin everything. At least they ruin some media tie-in books for me...