When Tony Archer points his revolver at Steve McGarrett, the closeup of the cylinders reveal blank cartridges in the chambers.
When Steve pulls Len Marks out of the chum box, Marks' hair is dry in the one shot then wet in the next.
When Grace goes down the water slide and reaches the end, Danny is seen close by in the far shot. When the shot is taken closer, Danny is not in the shot near her.
When Steve and Danny are talking about Danny's visit to the hotel with Grace, Danny's words "Maybe a little too much" are heard on the sound track but Scott Caan's mouth does not move.