Danny is seen getting into a boat moored on Oahu (Tripler Army Hospital is seen in the background) to observe Steve, who is undercover. Just minutes later Danny is observing Steve at a house on Hawaii's Big Island, which is over 200 miles away.
The amount of tape on each reel changes in subsequent shots from more on the left when rewinding (rewinding moves to the left) to more on the right when stopped (different angle) to equal amounts on both sides when played (yet another angle).
When Danno is taking photos from the fishing boat he's getting facial photos of people whose backs are to the water.
Undercover McGarrett goes to the length of taking luggage with him to the hotel when he assumes the safe cracker's identity (recently flown in from the mainland). When Swanson knocks the suitcase off the chair to sit down it is clearly empty.
Swanson's jacket had the words, "Muana Loa..." on the back. This was pronounced as "Mauna Loa..." and is a misspelling.