It Sounds like from the Movie "The Keep" a great horror movie from 1983.
You're absolutely right!
I have not seen the movie, but as a big Tangerine Dream fan I know that the soundtrack for "The Keep" was made by these guys.
It's awesome that you've seen the movie and recognized the music style. Do you remember anything about it? Is it worth watching? Well, maybe I should watch it because I already like the soundtrack.
The soundtrack for "Atemlos vor Angst/Sorcerer" by William Friedkin from 1977 was also made by them and I think it's really good. The movie is a remake of "Lohn der Angst/The Wages of Fear/Le Salaire de la Peur" from 1953.
A movie about driving two trucks loaded with highly explosive nitroglycerin through the jungle without exploding. ;-)
The cool thing is that the music was created first and the movie was build around the music.
Some people think I'm crazy for listening to this, but I love instrumental electronic music like that. Tangerine Dream made many film soundtracks in the 80s.
"Legende/Legend" by Ridley Scott from 1985 is another movie for which they created music.
But only for the American version.
In their early years (1970-1975) they made improvised, atmospheric, sometimes quite eerie and mostly melody free music. Later they started using a sequencer and their sound became more rhythmic and melodic. Unfortunately from 1987 on their music turned into boring elevator music.