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: When Oliver shoots Ted with an arrow, Ted falls down on the ground. The position of the arrow keeps changing from being perfectly in the center of the chest, to a few inches off-center, depending on the angle.
Continuity mistake: In the scene in the garden where Oliver and his sister stand by the headstones, Robert Queen's birth date is carved into the stone as 1958. This conflicts with the news report at the beginning of episode 1 when his birth date is shown as 1948.
Continuity mistake: In season one, Sara is a brunette in Oliver's flashbacks. In this season's flashbacks, she's a blonde (most noticeably the ones aboard the Queen's Gambit).
Continuity mistake: 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. (00:41:05)
Continuity mistake: In the flashback to when Oliver brings a pizza in and puts it on the bed, the box goes from open in one shot to closed in the next. (00:28:30)
The Man Under the Hood - S2-E19
Continuity mistake: In the first shot of Thea running out of Slade's car, she closes the door. In the second shot, you can see the door of the car open. (00:02:05)
Continuity mistake: When Bronze Tiger is stealing the prototype earthquake device, when the truck is leaving Merlin's garage, the street shown has street lights and a factory building, not a country estate driveway. (00:17:10)
Continuity mistake: When Oliver tries on his mask for the first time, he is not wearing eye make-up. When the mask is on in the next shot, he suddenly is.
Continuity mistake: During the hallway gauntlet, Oliver takes a guy out and ends up on his left knee. He then starts to turn right and draws an arrow, which doesn't make any sense because he holds his bow with his left hand and can't get a good shot from that position. What's more, in the following shot, he is turning to his left.
The Odyssey - S1-E14
Continuity mistake: When Wilson jams the pistol in Oliver's face, Wilson is holding the gun in his right hand. When the shot changes, it flips - he is suddenly holding it in his left hand, and his previous un-scarred left eye now has some scrapes around it.
Continuity mistake: When Oliver takes the circuit board out of the missile launcher, Wilson grabs the radio to get out of there. But when he says "Leverage", the radio is back where it stood.
Continuity mistake: When Oliver stabs the assassin with the poker, he pushes the thing all the way through, with the handle against the shoulder. In the next shot, there is a 3 inch piece of poker between the shoulder and the handle. (00:35:05)
Continuity mistake: When Oliver manages to wreck the Dodger's car, he skids his bike sideways and gets off. In the next shot, when the bike is in the background, he is no longer beside it, only to reappear in the next shot.
Continuity mistake: When Oliver drinks his tequila, the hand with which he holds the glass keeps changing.
Continuity mistake: Oliver chops off Malcolm's hand to end their duel. When Oliver hands the ring over to Nyssa you can see Malcolm lying in the background where he has been cut down with two hands intact, and the cut off hand nowhere in sight.
Blood Debts - S4-E10
Continuity mistake: When Conklin is whipping Oliver during an island flashback, the wounds from the whipping are visible, but after Oliver threatens to shoot himself unless Taiana remains unharmed he hands the gun to Reiter, and we get a good look at Oliver's back, wound-free.
Continuity mistake: Yao Fei takes the bow away from Oliver in one shot, then Oliver hands it to him in a following scene. (00:02:10)