At the end of the show, Klink comes out for inspection. At the time his collar is pulled up to block the wind. When the camera angle changes Klink's collar is down. When Klink goes to barrack's door the camera angle changes again and Klink's collar is back up. When the snow falls on Klink's head and they show his face, the collar is back down.
When Carter and Newkirk finally find the tunnel entrance, they clear the snow off the stump. When the stump is opened, any remaining large deposits of snow fell off. Seconds after they close the tunnel entrance, a German guard runs into the clearance, and the tunnel entrance stump is completely covered with snow.
According to the story line, the flyers were shot down and have been in the blizzard for 3 days. Yet, they are not froze cold, have dangling icicles, or are frostbit.
Carter is seen handing buckets of dirt to Newkirk out of the snowman. Seconds later, Newkirk and Carter are seen in the barracks, each with 2 buckets hanging from a rope around their necks and shoulders. It would take a lot longer to tie the buckets to the rope than it would be to just carry the buckets in. Update: The buckets come up and out of the snowman already tied together. This would have allowed them to be carried in the same way by the people in the tunnel, at the same time making it easier to lift them out through the snowman - as well as carry them into the barracks.
During several scenes the artificial snow used remains on various character's clothes and even bare skin when real snow would have melted.
When digging the tunnel under the sink, the sink drain would be going either down into the floor or curved into the wall. There was no sign of either having to be disconnected before the sink is moved.
Either way, there would be a bit of spilled water on the floor when the sink is moved. This also seems to be the same sink that is used for the sink periscope. No evidence of having to disconnect the periscope before moving the sink.
The 'snow' can easily be seen as fake, both by its regularness, and the fact that it is not melting when it lands on an individual.
Hogan says that there are 20 barracks, and the odds of them being moved to Barracks 4 is 20 to 1. This is not mathematically correct. They are in one barracks, there are 19 other barracks, so the odds are 1 in 19 to be moved to any one other barracks.
Hochstetter says the Gestapo barracks have been bombed, but does not say where. Was it in Hammelburg? Dusseldorf? Another city nearby? If it was any farther than this he would not be looking at STALAG 13 for the fliers. Update: It was not a Gestapo barracks, it was Gestapo Headquarters that was destroyed by the bomb. Also, Captain Morgan (Noam Pitlik) refers to the Underground not telling them where they were going. Therefore, the obvious assumption is that the Gestapo Headquarters in Berlin was hit, and the Underground helped direct the bomber crew to Stalag 13. Furthermore, it is reasonable to assume that Major Hochstetter had some idea of the direction the crew was heading and, knowing the history surrounding Stalag 13 and all the activities in the area, that he would make the assumption that the crew is there.
There were 6 flyers brought into camp. The normal compliment of a B-17 or B-24 is 10 men. That means either 4 did not survive, or a medium bomber (B-25 or B-26) was used for the bombing. There was nothing said about the missing crewmen; at that time of the war, the range is too far for a medium bomber to fly from England.