When Yukio is riding his motorcycle and suddenly comes across a kangaroo, when it cuts back to a front view of the motorcycle, you can see the ramp in the lower left corner of the screen as the motorcycle flies up and crashes.
When Yukio accidentally shoots his translator, he is first seen pulling back the slide of his 1911 pistol and the slide locks to the rear. The slide of a 1911 will only lock back if a) the slide lock is pressed up or b) the pistol magazine inserted is empty. Since Yukio knew nothing about firearms it is unlikely he would lock back the slide by himself, so the pistol that accidentally shot his friend was empty of any ammunition.
The goof item below may give away important plot points.
Flipped shot: When Colin shoots Boorjan in the motel room, his gun is switched from his right hand to his left, he is turning in the wrong direction, and the insignia on the top of his breast pocket switches to the other side.