Factual error: When Dexter is in the hospital as a child, the doctor says that Dexter has a very rare blood type, AB negative. Although it's very rare, the people with AB- can receive donor blood with A-, B-, AB- and 0-. AB- is a very good blood-type when you need to receive blood. While it is true that hospitals normally have to use AB- because of the complexity of other proteins (and to prevent adverse reactions), in case of an emergency, like Dexter's, and a shortage, a hospital will use a blood type close enough to not likely cause a reaction. In this situation, the hospital would give Dexter O-, B-, or A- instead as blood loss would normally kill a patient long before a suitable donor could be located, called in, admitted to the hospital, and have the transfusion set up. (00:31:00 - 00:32:00)
Continuity mistake: Dexter goes to the morgue to see the body of his father. When he first sees the body, he bends down, and the clock behind him reads 4:11. A moment later when he stands back up the clock is at 4:17. A couple of minutes later the clock is at 4:01.
Other mistake: Doaks says he saw the man's gun and chased him, lots of questions arise about what happened, but no-one mentions how a cop has no right to ask a person about a gun they have on them without probable cause. Doaks has no reason to even go after the guy.
Suggested correction: Florida is not an open carry state, so if the man was displaying a gun, the cop had probable cause to pursue and question. Even if the man had a permit to carry a weapon, per Florida law, that weapon must remain concealed. If the cop could see the gun, it was a violation of the law and the cop could not only question, but arrest him.
