They were going for a vibe like Stand By Me, with the kids in front and center as part of a coming of age movie. At the same time, they decided to throw Matthew McConaughey and Reese Witherspoon into the mix for some adult interaction (even though the two rarely interact with each other on screen).
It was surprising that they would decide to Make Matthew's character have two valued possessions on the tiny island he was hiding on: his gun and his shirt. The famously shirtless McConaughey still managed to find opportunities to take off his shirt to show off his pecks. As he plays the title character, he is very dirty most of the time, and he spends most of the movie sitting on a very small island in the middle of a river.
In the graphic above, it would seem like the adults take center stage, but it is ALL about the children. Admittedly, one of them has an epic nickname: Neckbone. I mean, come on! That is redneck gold right there. So, the two boys find our title character on his island, befriend him, and then get caught up in Mud's horrible life and terrible decision making skills.
McConaughey does an okay job, and so do most of the other actors, but the whole pace of the movie is very slow. It's speed is dictated by the fact that we're following these kids through the complexity of their lives, and a bit too much has been happening in their lives. It makes it hard to deal with their problems when you realize that their lives are just plain miserable and pointless.
Acting was good.
Direction was okay.
Story was slooooooooooow.
Dialogue was fairly bad.
Cinematography was not great.