I think the bad guy was a revived soldier who was haunting this cliffside house. I think the house gets torn apart and then the good guy and bad guy face off at the top of the cliff. The good guy takes a grenade and shoves it into the bad guy’s guts. The bad guy blows up, possibly while falling off the cliff into the ocean. This was probably an obscure, cheesy low budget movie. I saw it as a kid and don’t remember much of it.