aka Fire Monsters Against the Son of Hercules
How bad is it? It's one of the worst Italian Hercules knockoffs.
Should you see it? No.
Maciste (here called Maxus in English) was no Hercules and Reg Park was neither the star nor even the actor that one usually finds in the Italian superhero movies of the 1960's. Here there's two warring tribes (and only one fire monster, though 4 monsters in all) and Maciste helps the good guys beat the bad guys. The effects are very cheap and the editing is atrocious. It may be a pastiche of two edits, as the hero's voice keeps changing.