Revealing mistake: Near the end when Ace gets into his Cadillac, in the first shot facing the front of the car, there is a protective glass in front of Ace (the same width as the windshield) with the dashboard in between that glass and the windshield. Note the vertical edge of the glass is visible at the right side, and the rearview mirror's sticker on the windshield casts a shadow onto the second glass. During the stunt, the flames on the dashboard are between the glass shield and the windshield, keeping the actor safe from harm. (02:46:05)
Continuity mistake: When Remo Gaggi is talking to Andy Stone about Ace cussing out the Board, there's a pack of cigarettes beside Gaggi in his car. The camera angle changes to show Stone's face, who is outside the car, and when it flips back to Gaggi, there is a Zippo lighter in place of the cigarettes. The camera goes back to Stone, and when it comes back again, the Zippo is gone and the cigarettes are back. And to top it all off, not once did Remo smoke in this scene.
Other mistake: In the scene after De Niro's car explodes, they show him being put in the ambulance feet first. Patients are always put in head first.
Continuity mistake: In the scene where Sharon Stone is talking to Joe Pesci about how De Niro had his guys beat up James Woods, there are 4 security monitors on the desk behind Sharon Stone. First, the top left monitor goes out. Next only the bottom right monitor is on. Then all four monitors are off. Finally, all four monitors are on again. (01:18:05 - 01:19:20)
Revealing mistake: In the scene where Pesci's character is being buried alive, the body is quite obviously a fake: look at the mechanical way the head moves, and the movement of the chest intended to simulate breathing, not very convincingly.