This is definitely not the movie to see if you seek a good 80-90 minute soft action or love film for entertainment. On the other hand, it will take only two and a half hours of your time to see some of the most striking and colorful imagery of the roman world of all times - of which, every director has difficulty in escaping.
The final minotaur scene, I understand, is not on the original Petronius novel (it couldn't be). It is the "Fellinian moment" of the film. All of Fellini's films end up in some sort of non-sense apotheosis which take your feeling of being lost to the highest point -- and signals you, at the moment you were thinking you were starting to grasp it, that there's a whole lot more than what you can comprehend.
Fellini once said that he loved decadence much more than sound-mindedness, since the former was so much more rich in its imagery and colors.