Despite being a horror movie, John Carpenter stated on the audio commentary that he did this movie because it closely resembled a western to him.
John Carpenter had a good working relationship with James Woods on set. Apparently Woods has a reputation for being difficult to work with, but Carpenter got along with him just fine. They had a deal: Carpenter could film one scene as it was written; the other Woods could improvise. Carpenter found to his delight that many of Woods' suggestions were brilliant.
The film that convinced John Carpenter to stay in directing. Feeling burnt out after a string of critical and financial failures, John Carpenter had lost his love for filmmaking and was heavily considering going into retirement following the failure of Escape From L.A. because in his words "it stopped being fun". However, when Carpenter was offered the job for Vampires, he was intrigued by the promise of making a horror-western hybrid, something he had wanted to since the 70's. He made a deal with himself: make one more movie, and if it still isn't fun, retire. Carpenter would later go on to heavily enjoy his time on directing Vampires.
For this film, John Carpenter wanted to stay away from the stereotype of gothic vampires and wanted to make his vampires "savages" and not be "brooding loneliness in their existence. They're too busy ripping and tearing humans apart."