In the beginning of the movie when they riding to the check cashing place, Marcus is in the front passenger seat. When they showed the same scene the second time, he is sitting in the back seat.
When Marcus is shot by Justice in the beginning of the movie, the money bag flies to Justice. The second time, the bag goes out to the side.
In the scene where Marcus says "Crack meant money, money meant power, power meant war," a blue 1965 4 door Impala drives up to 3 guys standing on the side walk. when the scene switches to showing those guys being shot the car changes to a Blue 1964 4 door Impala.
When Marcus leaves the hospital to "take care of something" his facial hair is thick. Later that night when he returns home, his facial hair is gone.
When Keryl, Marcus, and Justice go to take revenge against the Colombians, Marcus gets out of the car immediately after it stops. In the next shot, he is still inside chatting with his buddies about the weapon.
When Majestic is discussing killing the police to Marcus, the shot of the Uptown station house has the same figure ascending its steps in both shots, revealing that one shot was used twice instead of actually using two separate shots of the same location.
When young Marcus is about to "protect" his mom when she's confronting the drug dealer who's working her corner, Marcus' weapon was a club, that particular club didn't come out until the early '90s.
When Bama calls Justice out for fidgeting in his car, Bama is heard saying, "I'm still right 'cause I could have been wrong," but his mouth says, "...right."