When Vegard first begins searching for Sara, as he is riding through the area there is one scene with visible sled tracks from previous takes.
The skull badge on Colonel Herzog's hat changes from crooked to straight throughout the movie.
None of the Nazi helmets have insignia.
When one of the zombies climbs in a tree one can clearly see that his hand is skin colored and not greenish as it is supposed to be. All the zombies are greenish in skin color.
When zombies rip one of the men apart, it's very obvious that the legs they are holding are from a mannequin.
The tagline is misspelled, it should be "Eins! Zwei! Die!" instead of "Ein! Zwei! Die!" It lacks the "S".
Herzog is described and credited as a Colonel. However, he wears a cap with a Totenkopf insignia, making him a member of the Totenkopfverbände (since 1941 part of the Waffen-SS). In the SS, he would have been addressed as Standartenführer.
One of the zombies (one of the two chasing the girl up the tree) is wearing a white (snow) camouflage jacket. The jacket shows plastic parts (or is completely made out of plastic) which can only be found at modern day jackets. Maybe the zombie took it away from a earlier victim but as all the others wear "original" war gear this is supposed to be a WWII Jacket - and is way too modern.
Chris claims the movie April Fool's Day (1986) was made in 1984, when in fact, she is off by two years.