When the prisoner cage is being hauled along the hangar, it's broad daylight, as is obvious in the matte shot with the outside view and in various windows and openings in the background. Wenn the cage is set down however, it's suddenly dark outside the hangar door.
Jason undoes the knot in the left string holding Karina's dress with his teeth twice.
When the heroes walk trough the fog on Wendon's planet (just before they are attacked by amazons on their unicorns) the folds in the backdrop on the set are clearly visible.
Even though the main theme of the movie is the scarceness of water in the galaxy (!), it is only referenced in a few scenes when background extras are fighting for drops of water in the pirate hideout. Its mostly ignored throughout the movie and the main characters seem to have no problems, even seen drinking regularly throughout the movie.