Movie can be seen playing on a tv in the 2000 film Merlin: The Return, also written and directed by Paul Matthews, which itself was riffed for RiffTrax by Mike Nelson, Kevin Murphy, and Bill Corbett of Mystery Science Theater 3000 fame.
The alien's roar was stolen from 70's King Kong.
This movie was riffed for RiffTrax by Mary Jo Pehl and Bridget Jones under its alternate title, "Deadly Instincts".