Continuity mistake: In the scene when the Kurgan has been shot by the paramilitary mortal in the alleyway, Kurgan makes his getaway by taking possession of a green Chevelle, with an old woman still inside. As the movie cuts to the car emerging from the alley at high speed, it is no longer a green 1971 Chevelle, but is now a green duster.
Continuity mistake: When Conor and Heather are making love outside, just before Ramirez appears, she says to him "You can do that to me forever if you'd like, my lord". Conor is then seen from above as he turns his head slightly and looks at her. The angle changes to a sideways shot, and his face is now turned directly upwards to the sky, and his eyes are closed. Back to the first angle, and he is once again looking at Heather with his head turned.
Continuity mistake: In the scene where Connor lops off the head of his first opponent in the Garden car park, the man's head flies off some distance to the right of the viewer Connor's left. However, in the next couple of shots, the head can be seen lying on the floor to the left of the body (or alternatively, on Connor's right). It's also a bit closer to the body, but the main issue here is that it switches sides instantaneously.
Continuity mistake: In the final battle, it is impossible for Brenda to have gotten from the roof to the large "final fight" room as portrayed in the film. Brenda is seen on the roof, then shortly after, barging against the wall of the room. Too little time has past for her to have gotten from point A to point B.