Revealing mistake: Before Frank drives off the overpass onto the transport trailer, in the close-up there is sand placed at the top of the back tire (but the rest of the tire is clean), which creates the effect of the dust cloud as the back tire begins to spin. (00:07:45)
Revealing mistake: On the transport trailer, Frank leans out his car window and dramatically fires at the ramp's tall lever control in a close-up, located at the rear of the transport over the tires. The problem is that the trailer has no such lever control, as seen in the previous shot before it drives under the bridge overpass. (00:07:55)
Revealing mistake: After his car explodes, Frank exacts revenge on Wall Street's men. With the last one he takes out, before he fires the man's gun at the walls, he leaps into the air, flips, kicks the man back and then lands. The Asian stuntman, who has more hair than Frank and wears shoes with tread detail, unlike Frank, is too obvious. (00:30:05)
Revealing mistake: In the hospital room scene, Wall Street stuffed a cloth into his employee's mouth, killing him. Wall Street then hooks the life support wire to the other living guy. As he walks out, you can see the dead man's neck moving as if still breathing. (00:38:25)
Revealing mistake: When oil covered Frank breaks off the bike pedals, and slips his boots into them, in a following close-up we see an extra strap around his boot and the laces are actually tied over the pedal strap, to keep them secure. (01:14:20)
Revealing mistake: As Frank is about to be shot in the warehouse, he pulls the giant thug in front of him as a body shield. They both fall back through the window and hit the water. As they do, we see the back of Frank's hair, which is something of a shag style. It is far from being Jason Statham, as throughout the film his buzz cut is almost to the point of him being bald. (01:15:10)
Revealing mistake: As Frank is about to be shot in the warehouse, he pulls the Giant Thug in front of him as a body shield. They both fall back through the window and hit the water. Since an oil drum is thrown on the water then shot to light the water ablaze, Frank needs more oxygen. He goes to the Giant Thug to extract some from his lungs. Right before they cut to close-up, you see the Thug is a painfully obvious, stiff-armed dummy. (01:15:40)
Revealing mistake: When Frank's discarded paraglider has blocked the windscreen of the car, causing the collision, the stopped car explodes slightly *before* the actual collision (this is just noticeable even at normal speed) and the explosion is visible in stop-motion as originating inside the car (visible through windscreen) as opposed to the gas tank.
Chosen answer: You notice that Frank removes those items from a bicycle frame. Those are stirrup-style rat trap bicycle pedals. They have serrated metallic edges which supposedly give Frank traction on the concrete floor, despite the oily mess.
Charles Austin Miller