A fine "B" movie cast is wasted by using awful production values in a project that likely ran out of money before it was finished. The tacked-on ending without a doubt uses different actors than the on-screen talent (Grant Williams, Mala Powers, Denny Miller, Bobby Van). Probably the WORST special effect is the destruction of the earth. "The Doomsday Machine" gets a "3" from me because it was at least always coherent. It's sad whatever happened during production prevented the movie from being filmed as intended. I feel especially bad for Grant Williams, a fine actor, who was likely blacklisted because of his sexual preferences, not to mention a well publicized feud with Jack Webb, then director of production for Universal. Better William be remembered for "The Shrinking Man" and "Hawaiian Eye" than this crap. Ditto, Mala Powers for "The Time Travelers".