When Felicity trips and drops the champagne bottle, Oliver catches the bottle with his thumb facing the bottom. But when he puts the bottle on the table, his thumb is now facing the top of the bottle.
When Oliver is forced to do a HALO jump by ARGUS in order to infiltrate Lian Yu he has no oxygen. HALO jumps are made from altitudes of 25,000 feet and above and military personnel always use oxygen bottles when doing them. In reality Oliver would have lost consciousness shortly after exiting the plane.
When Oliver is thrown from the plane, he is wearing the parachute like a backpack, with none of the lower straps secured. He would have been separated from the parachute harness by either the wind or the jolt of the parachute opening.
When the ARGUS agent is explaining to Oliver what he needs to do, the sub title has the agent saying "shoot" instead of "chute.