The sledgehammer lying on the hood of the red car, changes position and appears and disappears between shots.
When Wilbur is whacking the gang on the dock, the red car is under the sunlight. Then when a guy jumps on hood to hit him, the car is in the shadow like one hour or more has been passed. Then after a few seconds the car is again exposed to the sunlight.
Rotor blades of the helicopter flying the cameraman are clearly visible in some of the opening shots.
When Matt Kirby is hitting bad guys with two bowling pins, the pins bend as they hit, showing that they are rubber.