Left Behind - S3-E10
Continuity mistake: In the previous episode Ra's al Ghul stabs Oliver through his chest, just below his left pec. When he pulls out the sword, a wound is visible. (However, seconds later, the wound is absent - different mistake). In this episode he is shown with a wound much lower (in his lower abdomen) and also later, with a bandage around his waist instead of his chest. (00:09:30 - 00:41:30)
Continuity mistake: Before and after the Beetle's battle armor is fried by May Parker activating the jet engine, the appearance and arrangement of the building in the background changes between shots.