Goofs

Carver is shot once only, directly in the head, but when his corpse is shown a few minutes later, the bullet wound is on the left chest.

When Ellis confronts Mud on the beach and then runs off, the left leg of his jeans are covered in mud. In the very next scene his pants are clean.

Mud emerges from the cabin of the restored boat. The bandages on his back are wrapped significantly differently to when he lay face down on the bunk a minute earlier.

When Neckbone calls Mud for help after Ellis falls into the snakepit, Mud grabs his shirt off the limb, sticks his arms in, and takes off running with the shirt unbuttoned. In the next shot as Mud runs towards the camera, his shirt is fully buttoned.

Mud delivers Ellis to the hospital. The orderly & patient near the entrance move significantly between two camera shots.

Ellis and his mom come across a roadblock and police checkpoint of State Troopers checking cars for Mud. The Arkansas State Trooper that comes up to the window is wearing the wrong uniform. His badge is wrong, and his shirt is wrong. He has one of the cloth badges on his right shoulder, but it is the wrong shape for State Troopers. And he has an American flag on his left shoulder. Arkansas State Troopers have the cloth badge on both shoulders, not an American Flag.

Mud says that the same snake antivenom cannot be used twice on the same person. While it is true that repeated use of first-generation antivenoms can cause severe allergic reactions, modern antivenoms can be used repeatedly safely.