During the shooting of this movie the filmmakers stumbled across a forest fire that they decided to shoot and subsequently incorporate into the story.
This movie was shot with an old newsreel camera.
An elaborate sequence involving rats was planned, but ultimately not filmed due to constraints in both the budget and schedule.
The live action scenes were shot in three weeks. Moreover, the special effects sequences took five weeks altogether to film.
The legs for the aliens were done from molds that were built on pop sickle sticks.