As a avid watcher of Mystery Science Theater 3000, I am used to the bottom of the cinematic barrel. However this movie is so irritating, it is in a category of pain all its own.
First, John Allen Nelson makes a particularly loathsome 'hero' as Deathstalker. His arrogance comes off angering, and his attempts at sexuality come off as repulsive. You don't believe that anyone has ever desired his help or praised him. Plus, his accent lasts about 2 lines.
Second, the support characters are laughable. The princess is wooden and unpleasant. The other characters are overacted and thoroughly unbelievable-especially in the case of Thom Christopher (Troxartas).
Lastly, it is possible to make a good movie with a low budget. It is also possible to turn this type of movie into light-hearted and fun. But, with the hideous characters, bad editing, and vague plot, this movie feels pained and leaves you caring less what happened and praying they didn't make Deathstalker 4.
The only positive thing I can say is that the MST3K crew does a decent job of poking fun at it, although it is obviously painful for them as well.