Continuity mistake: In the fight sequence (just before Paul stabs the French soldier), supposedly a lump of rock strikes Paul's helmet, but doesn't dent it. When it cuts to the closeup, the helmet now sports a large dent.
Continuity mistake: When the class has decided to join the army, one student is twice seen writing on the blackboard. (00:08:30)
Continuity mistake: When the main German soldier (Paul) is regretting stabbing the French soldier and is attempting to help him, the Frenchman puts his arm on this chest. In the next shot, his arm is off his chest and is lying on the ground.