When a villain seems dead, he never is. He will always be allowed one, and sometimes two resurrections. The hero will frequently see him coming, even if his back is turned. If he doesn't, a friend will finish the villain off. The bad guy usually kills his henchman for failing, yet don't seem to run out of loyal henchmen.
Bad guys lurk until their presence is revealed by a flash of lightning.
The bad guy, having finally gotten the good guy into his clutches, will usually spend a few megalomaniac minutes gloating over his victory and his opponent's downfall. This increment of time will prove just enough to allow the good guy to figure a way out of his predicament, or just long enough to allow a rescue attempt. The bad guy, instead of simply offing the captured good guy on the spot, will devise some sort of drawn-out, fiendishly clever method of execution that will take enough time to allow the good guy to figure out his escape. When a villain seems dead, he never is. He will always be allowed one, and sometimes two resurrections.