Unresolved plot threads
Was this film originally planned to be part of a series? I ask because there are 2 rather big unresolved plot elements to this film.
The first is the king out to kill Jason. He sends Jason on a quest that he hopes will kill him because he knows he has been deemed that he cannot do it himself; otherwise he dies. This element of the plot if left dangling by the end of the film.
Then there's the fleece itself. The quest ends but then what happens with it? It's almost as if this is intentional, leaving the film open to a sequel that was never made.