Although coming after three Star Wars, Krull & countless others, this movie would look outdated in the 1950s... 1 SFX mostly consist of 1970s videogames effects such as bolts etc; annoying after a short while. You also get a SFX creature that looks like a poor man's version of some tier-IV Harryhausen monster.
2 sets are mainly ruins in the countryside, with papier-mache temples and miniature cities or abodes that makes 1950s Japanese monster movies look like flawless perfection.
3 Plot is paper extra-thin...Hercules must find Zeus' seven golden thunderbolts stolen by conspiring gods & zombie tyrants.
4 action mainly consists in retarded, muscled-up Hercules ( check the variety of facial expressions ) wrestling cheap 1970s videogames effects.
5 acting award goes to Milly Carlucci (third Carlucci show-biz sister with Anna & Gabriella ), which says all.
6 SFX make other tier-II Italian salad bowl movies such as L'UMANOIDE & STAR CRASH look like masterpieces.
Well, considering that Ferrigno's main acting exploit consisted in impersonating a retarded green monster, wearing a whig and green espadrillas, we ought to be lenient.
Watch it & forget about it.