Visible crew/equipment: In the "Straighten the Rug" dance scene, when Nick runs up the wall and does a backflip, it is clear that he is being held up by wires. The filmmakers did a good job rotoscoping the wires out against the wall, but when his legs pass behind the wires and harness, they have not been taken out at all and are visible. (Freeze-frame when he is completely upside down for the best view.). (01:07:10)
Visible crew/equipment: The moment the cow goes away from the herd, we can see a boom mic moving up right behind the corner of the tower. (01:12:25)
Visible crew/equipment: As Nick jumps off the piano, the tip of the boom mike dips into the shot.
Visible crew/equipment: When the "blind" spy is talking with the British agent, the lighting rigs are reflected in his shades a few times.
Chosen answer: The actors were weighted down with lead plates. Oxygen tanks were kept just out of picture, and the actors used them to breathe between takes. The takes were short enough to allow the actors to hold their breath through them. The short takes were then cut together to appear as one long fight. Sound effects were added post-production.