Plot hole: Zharko's process of using the dead bodies of agents and reviving them could only work if he had them at about at most a day after they were killed. Since his secret lab is on a deserted island in the middle of nowhere, they could not have got the bodies to him in time. The Chief also said that the bodies suffered severe damage, so their ability to move would be seriously hindered, but they work fine.
Plot hole: When the watch is sucked to the island by the magnet, where was the sailor that the watch was attached to?
