I have seen this move some 2 decades ago on TV. That would be around 1998 to 2003.
It was live-action (real people, not animated).
I vaguely remember the theme to be that of some pseudo-Greek-mythology setting.
The movie might have played in a version of Atlantis.
The theme was clearly fantasy.
The hero character tried to escape from the island (or city) where it was set.
There were more people that the hero tried to save / wanted to be saved.
These people would slowly turn into animals over time while working themselves to death.
I think there was an upper class of people or similar that suppressed the others.
There probably was a romance subplot.
I wish I could be more precise, but that is one of the many movies I've seen on TV as a kid. And while I can clearly remember titles such as Jason & the Argonauts, there's lots of movies I only remember snippets.