Continuity mistake: When Keanu and Jeff are on their way to the building at the start of the film, their car flies over a hill and lands back on the road. The right hand front wheel takes a really nasty knock as it lands and looks ready to come off, and yet in the next shot they arrive safely with no apparent difficulty driving the car. (00:06:00)
Stupidity: Howard has the opportunity to shoot Jack at the end, but doesn't for no discernable reason; he's already committed multiple felonies, and shooting Jack would help cover his tracks all the better. In fact, he could even have just taken the cash onto the subway and left Annie behind while staying in full disguise as a cop.
Suggested correction: Howard Payne's taunting dialogue in the subway station suggests that he wants Jack to live a long life, tormented by the fact Payne was able to beat him. He doesn't become intent on murdering Jack until the dye pack goes off, ruining the money. After that, he tries to shoot Jack but runs out of bullets, then decides to beat him to death with the detonator but fails.