Continuity mistake: For the final confrontation with the rogue Delta agent, Magnum moves from the van where he (foolishly) left unguarded the bad guy with the damsel taking cover behind one cable drum, to another. He looks back in a close-up as he clings to the drum, and the van is far in the distance behind another drum. He then looks forward, towards the tower where the agent Tobin is hiding, and decides to move. Only, we see that his sortie is beginning from the large spool the van is parked next to. (00:42:50)
Continuity mistake: Magnum runs away from Tobin's fire, ducking by a large piece of construction equipment. In the closer shot that follows, that element casts a large shadow Magnum repairs in, and that was nowhere to be seen earlier. (00:43:20)
Continuity mistake: When Agent John W. Newton is shot to the shoulder, he drops his M-16 behind him, a couple meters above his head. Magnum retrieves it from the vicinity of his foot. (00:46:00)
Revealing mistake: Right after Newton drags his girlfriend to the ground and before Magnum spots him and takes aim, Eric walks at the top of the barge...but it's not the Eric we see then in close-up; it's a burlier guy dressed the same.
Audio problem: When she comes around at King Kamehameha and especially in the scene by the tidal pool, Rebecca Holden's lines are very noticeably dubbed in.