Continuity mistake: When the suspects are in the garage after Saul, Saul drops a gun and Keaton kicks it over to McManus. However in the next shot McManus picks up a different type of gun.
Continuity mistake: When we first see the Hungarian guy lying in the hospital he is burned over most of his face, however his eyebrow is still there. In a later scene, his eyebrow is gone but his eyelashes are still there.
Continuity mistake: When McManus and Keaton are clearing out the boat, the time of day outside (as shown by the daylight) changes from shot to shot. It should be dark during the entire scene.
Other mistake: The burned guy who's supposed to be Hungarian keeps making bad language mistakes, although his pronunciation is great.