Did anyone notice these TWO things?
1. The guard Sylvio, the waiter and the fat smuggler, all look the same! It's like the animators were too lazy and just recycled the same character. See for yourself: http://img17.imagevenue.com/img.php?image=995085589_Riocharacters_122_ 106lo.jpg
2. Almost all of the native creatures (brids, dogs etc.) of Rio de Janeiro are voiced by American actors. I'm not saying that's a bad thing but if they had been voiced by Hispanic actors, then their accent would have added a nice flavor to the ambience of the movie. That way the audience gets the sense that these characters are indeed Latin Americans. Take, for example, "Ratatouille" which is set in Paris and so a majority of the characters have a French accent. Such small things can make a difference to a movie, IMHO.
"I'm the dude playin' the dude, disguised as another dude!"