Continuity mistake: Near the beginning, Jake drives a motorcycle out of the warehouse shoot-out and spins out as police cars converge on him. He has blood coming out of the right corner of his mouth, the shot changes, cuts back to him and the blood is on the left, then right again in the subsequent shot.
Continuity mistake: When you first see the picture that Jake drew of the woman in his art class, the dragon has no scales. But, when they show the close-up, the dragon now has scales drawn.
Continuity mistake: In the warehouse scene, Jake gets a gun off a bad guy. He hides behind a wall and fires a couple of shots. His gun locks back in the empty position. In the next frame, Jake starts shooting again with the same empty gun.