When Gary attacks at the pool party, he picks up a couple of revolvers and fires dozens of shots from each, even though they'd only hold six and he never had time to reload.
Later in the film, where Gary Daniels is fighting on top of the car on the bridge, the stunt double can easily be recognized, since he's larger and has dark brown hair, while Gary Daniels is blonde.
The stuntman who does the fight on the car is being held by cables from inside the car. These cables are visible various times.
A wire is clearly visible when Gary Daniels is jumping away from the exploding white limousine.