Continuity mistake: When Joe is complaining about missing the football match and Sgt. Wells says "Yeah, well it's nothing like this at all, is it Joe?", Wells is holding his hand under the front part of the machine gun. When it cuts we can see him resting his hand on top of the front part of the machine gun.
Continuity mistake: When Cooper locks himself in the bedroom towards the end of the movie and looks for a way out, the wash basin does not sit on its support, a gap can be seen, but the next time it's seen it sits flush with the support. Also Cooper kicks at it rather tentatively actually not making contact a couple of times before a feeble looking touch sends it crashing.
Continuity mistake: In the scene where Ryan tells Cooper to shoot the dog, Ryan pushes the gun parallel to Cooper's chest, the barrel is horizontal. As the camera view changes, the barrel's direction changes, pointing up at a 45 degree angle. The pistol continues to do this 3 or 4 times as the view switches back and forth.