(at around 46 mins) After Nicky gets sprayed with mace on the fire escape outside Valerie's bedroom, he stumbles backward and begins to fall over the railing. In the next shot, however, his body is falling forward over the railing.
(at around 3 mins) At the very beginning when Nicky is "air jamming" to Van Halen's "Runnin' With The Devil" (which is playing on the right turntable), the turntables have no covers up until just before Jimmy The Demon walks in, then they are covered after that.
When Nicky is playing basketball against Cassius, and Nicky has the ball, when the picture shoots in to Cassius, he appears to be holding a basketball as well, although when the shot cuts back to both of them in the picture, Cassius isn't. Then, when the shot goes back in to Cassius, he's holding the basketball again.
(at around 41 mins) Nicky holds the jacket from the Chicago V album. The song he plays ("Does Anybody Really Know What Time It Is") is from Chicago's first album called Chicago Transit Authority (or Chicago I).
(at around 21 mins) When Adrian is possessing the Cardinal, the possessed cardinal is standing barefoot on a steaming hot pizza. It's hard to believe that no one in the church would notice the steaming hot pizza, but it's even harder to believe that no one in the church would notice the possessed Mayor. He stood up in front of the crowd, with tin foil wrapped around his feet like shoes.
(at around 1h 18 mins) After Nicky has fought Adrian for the final time, two girls in back of Nicky have no jackets on in one shot, and then are wearing jackets in the next. In the third frame, they again do not have jackets on.