Saw both the original 1977 version of CET3K and the 1980 'Special Edition' when they came out. (The last one on a double bill with 'The Black Stallion'.) Yeah, the Mothership rising over the back of Devil's Tower makes no sense, but, damn, is it cool looking.
(As an aside - my father's friend from basic training and the Air Force went to High School with Richard Dreyfuss. I've seen the yearbook photos that prove it.)
Logan's Run - a movie that starts off good, but kinda falls apart once they leave the domed city. Having now read the book (thanks to my local library) and watched videos on YouTube about the various 'Logan's Run' that never were, I'd like to see a remake or mini-series on HBOMax or some other streaming service that incorporates some of the ideas from the novel and various screenplays.
Battle Beyond the Stars - a sci-fi version of The Seven Samurai/Magnificent Seven. Good, cheesy fun, with Sybil Danning threatening to explode out of her costume, and early FX work by a young James Cameron and Bill Paxton.
Westworld - A good idea directed in a flat, TV style. It is a bit of nice subversion that the nerdy Richard Benjamin character is the hero/survivor of the movie and not James Brolin, as you would expect. Yul Brenner is a prototype Terminator for the last third of the movie, relentlessly stalking Richard Benjamin through Delos. What struck me upon a recent re-watch was that the last third or so of the movie, once James Brolin is shot, is almost completely without dialogue. Except for a brief exchange with a Delos technician, who's quickly shot dead, the only sounds are Richard Benjamin's heavy breathing and Yul Brenner's footsteps.
Space Raiders - If it's the movie I'm thinking of it reuses a lot of the footage from Battle Beyond the Stars, as a way to recoup Roger Corman's investment.