Continuity mistake: There is genuine wartime footage of Spitfires of the the right type for the period, but other scenes have later (maybe even postwar) versions flying about.
Continuity mistake: When William Holden is laying on his bunk and first notices the shadow of the hanging electric bulb, he turns around to look at the bulb, but there is no light source beyond the bulb to cause such a shadow.
Continuity mistake: After 1st Sgt. Milton Warden breaks the bottle to stop the fight between Pvt. Angelo Maggio and Sgt. James R. "Fatso" Judson, he throws the bottle in a corner. In the next shot, he's sitting down with the broken bottle on the table in front of him.
Continuity mistake: In a scene supposed to be after the ship has been fitted with radar, it is shown entering harbour with the 'lantern' removed and the aerial covered, which is how it's shown before the ship has the radar fitted.