After Caine shoots inspector Switzer he can be seen holding a Beretta 92F instead of his service gun, a Heckler & Koch P9S.
Diana's lipstick shade is completely different at the end of the scene in the autopsy room than at the beginning.
When the White Boy infiltrates the police station he burns through an iron bar grid with a torch. When he's done, the grid falls off in one piece, without any cut ends showing.
When the bad alien kills his first victim using the heroin and head extraction, he rips the power line out of the load box. The power goes out in the building except for the neon "Open" sign which stays lit. There is no reason for the neon sign to have a separate power line from the rest of the building.
Crew members and boom mike reflected in the autopsy room light while the cops are talking to the coroner.
Smith's stuntman is visible the first time he's hit by Talec's disc and is sent flying through the air.
After Caine delivered the heroin to the liquor store, Al Leong gave him an empty case, showed a gun, and left. Without taking the heroin he just hijacked. Both cases are still on the counter ~0:49:50.
Brian Benben carries a 38 revolver but by this time the FBI had already been thru the Miami-Dade Shootout and had transitioned over to 9mm automatics.