Revealing mistake: When they are learning how to throw knives, the guy gets one thrown through his hand. If you watch this carefully, blood starts coming out of his hand before the knife hits. (00:28:45)
Continuity mistake: As the Roger Young is breaking up, the ship's captain is running from the bridge and falls down with the large door descending and striking her midriff. As it hits, she spews blood from her mouth against the side of the door in a arching/sweeping motion. When Carmen returns to help free her, the blood is not displayed in the same pattern, more concentrated to one area as opposed to swept. (01:44:10)
Continuity mistake: In the scene where Rico is first in boot camp and Dizz says she is being transferred to the unit, she gets ready to fight the drill sergeant. She drops her papers, her jacket, and her bag. It cuts away for a few seconds, then goes back to the drill sergeant and Dizz in fighting stance. The piece of paper is farther back than before, this can be overlooked because of wind, perhaps. But the jacket and bag are both gone. (00:25:55)
Continuity mistake: Rico is running up the ramp to capture the red flag and drops his gun; it lands with the strap towards the top of the ramp. In the subsequent wide shot, the strap is towards the bottom of the ramp. (00:37:15)
Answer: The card face up is the one he's trying to guess. The card that flips over is his guess (you can see him hit a pad when he says "ace of spades".) So he is trying to use mental powers to guess the card that is face up (which he can't see as he has his back to it), and (presumably so the computer can track his results better) he makes his choice on a keypad, which then turns over the card on the screen (which is why the card is what he said, yet still wrong).
Gary O'Reilly