The ransom message sent to McGarret is on a tiny reel-to-reel tape. He asks Danny to set it up on the tape player. When next seen the reel has not only become a larger size, but much more tape has been added to the reel as well. The short ransom message is also apparently somewhere in the middle of the bigger tape, given how much is shown on the take-up reel.
When Danny raids the old warehouse, he is wearing a dark colored suit. When he kicks in the door and enters, his suit is a light tan color.
In one scene McGarrett is pacing in his office with dark blue suit pants, no jacket at this time. He received the phone call that the kidnapped boy has been found. He grabs his jacket and runs off.
The next scene he is returning the boy to his father and when he gets out of the car his suit is beige.
The next scene he follows the father into his house/office and he's again wearing the blue suit.
In the final shootout scene on the dock, McGarrett fires seven rounds from his five shot revolver without reloading.