When Gordon is being tortured, his missing leg changes from his left to his right one and back again between shots.
(at around 8 mins) When everyone gets off the coach after it stops at the fallen tree, dark vehicle tracks have appeared in front of the coach which weren't there in previous shots.
(at around 1h 17 mins) When the land-mine that Richard is stepping from explodes you can clearly see that the explosion takes place in a completely different part of the forest; the tree on the left side of the screen which wasn't there before, the soldiers balancing over the horizontal-tree are completely gone, the background lighting is completely different).
(at around 46 mins) During the paint ball scene, we see characters get shot with paint. In the scene with dialog the paint is missing from their clothes.
(at around 35 mins) Harris pours himself water twice. He grabs the glass when Maggie says "Everyone calm down", then again when she says "Jill come with me".
(at around 31 mins) The Russian troops in the flashback are wearing currently issued German Flecktarn camouflage.
(at around 2 mins) When George is hanging upside down it is clearly visible that his nostrils are blocked, this to prevent blood from seeping into them.