Parker steals a blued M1911-type pistol from the hunters' motel room and it ends up in his duffel bag. Later, the blued M1911 has been replaced by a nickel-plated M1911, Ross's "best .45" from later in the film.
When the driver is shot in the right ear (blood everywhere) at about 17:20, the car goes out of control. When the car veers around the tree and goes skidding on two tires (about 17:38), we see the driver's right ear (17:39) - it is now uninjured.
When Parker slides under the garage door as it is closing (twice) at Melander's house, he would have broken the infra red safety beam, so the door should have stopped and re-opened, alerting Mr. Rodrigo and his gang.
After Parker steals clothing and items from the hotel room belonging to the hunters it is raining. The rain is obviously not real since it moves to cover up the entire frame as Parker is walking. Also the rain falls in an arc suggesting that it is not falling naturally.
When the SUV goes out of control following the carnival job and goes up on two wheels, one of the shots clearly shows the SUV's lights indicating it is in reverse gear, even though the car is always accelerating and moving forward throughout the scene.