When Hercules and the antagonist bow/arrow target practice, the 1st arrow by the antagonist sticks but misses the center target. When Hercules helps a young man shoot, the 2nd arrow hits the center mark, but the 1st arrow is not only missing, it left no visible mark or hole on the same target. [Correction: The first arrow is visible. It's where it hit.]
When Hercules crushes the lion with his bare arms, the reverse angle shows the lion with a happy contented look on its face, obviously enjoying being snuggled.
After Hercules kills the lion and drops it to the ground, the dead lion blinks.
Obvious stunt double for Iole when Hercules rescues her from the runaway chariot at the beginning of the movie.
Hercules offers Iole a chunk of roast beef, but Sylva Koscina's bite at the joint misses by inches. However, she still munches at the imaginary meat and then complains of being too full.
The female dancers are wearing modern costumes.
Hercules asked for and was granted the removal of his super strength, yet he was able to pull down two building pillars à la Samson.