When Lansing gets into his car at the end he knocks askew the sunglasses atop his head, but the next cut shows them back in place.
Ted is holding the book in his left hand, when they cut to the close-up the book is in his right hand as he turns to run. The book is back in his left hand as he runs down the street. The book is back in his right hand in the next scene as enters the parking lot.
An average person run about 15 to 18 MPH, and yet the man manages to stay ahead of the speeding car which can't close the distance between them for the entire length of the parking lot, about 200 feet.
The hit man uses a suppressor on a revolver.....which would be ineffective. A revolver doesn't have a chamber - just a cylinder. The gases can escape before the barrel.
The car crash was not violent enough to cause the assassin to smash his head into the steering wheel. The wheel fell off and the car dragged to a stop, rah up on the curb and came to a stop in a hedge. Not only that, but the woman and baby were completely unharmed sitting in the seat right next to him.
When McGarrett hangs up there is a dial tone, but there is no dial tone when the party you are speaking to hangs up until you hang up and lift the receiver.
When Bo Lansing (Mark Gordon) was looking in the phone book in Ted Reynolds' (Mark Jenkins) apartment to call the neighbor's phone some numbers begin with "555" and others begin with "KL5" As far as the phone dial goes, they are the same, and phone books either have the numbers OR number/letter combinations, but not both.
After Five-0 had sabotaged Bo Lansing's (Mark Gordon) Lincoln Continental, they forgot to put the hubcap back on.
There is no expiration date on the library card.
At the end, it is odd that Lansing fails to observe Danno, who is up against the wall on an external fire escape stairway with a rifle. He and his hostages pass right behind Danno, who should have moved to the stairway going to the next level when they were behind the wall. If the very careful Lansing had turned to the right for a second, he would have seen Danno.
The letter Steve looks at had no description of the culprit (thanks to freeze frame on the DVR), just a narrative of the events, but later Steve reads the same letter and it has a complete description.
The name on the library card is Theodore R. Reynolds, but the hit man checks names in the phone book with different middle initials, like C and L when it is clearly R.