This is a pretty fun peplum, made because Jayne Mansfield took it so her then husband Mickey Hargitay got to play Hercules. She got to play two roles, that of Deianaira and Queen of the Amazons, Hippolyta (who takes Deinaira's form at one point in the movie). Mickey is OK as a beardless Hercules as well. The movie was originally known as THE LOVES OF HERCULES but was changed to the other title when released to TV later on.
The Hydra has three heads and is a full sized prop. Doesn't really move like a Rimbaldi creation, but one never knows about such things. There's also a strange ape/caveman monster in the movie. It just appears to menace our hero, but those are always a fun addition to these movies.
There are also tree-men in the movie, the poor souls who were Hippolyta's lovers until she got bored with them. They are kind of creepy and kind of silly all at once, and someone else can make the "wood" joke for the Queen. She's not a pleasant person and gets her just rewards in the end.
Jayne is pretty good in her roles, as good as both the script and direction will let her be. Her story is fascinating as well by itself. She was pregnant while filming the movie.
The plot is a little more complicated than most of these, but not too bad. Hercules' wife is killed and the evil Licos, who frames the King of Ecalia. Licos then frames Hercules as well, all because he wants to rule the kingdom and doesn't want to woo Deinaira properly. Some men are just dumb. Unfortunately I couldn't tell if the two main stars were dubbed or not, since I watched it online and the sound isn't great. I liked it though.