> Alien in 1979
I think this might be your nostalgia. The thing looks different in different scenes, and there's a scene that feels like it's a guy inside from the way it moves. So I disagree that Alien is peak special effects. (still peak over things. Peak ambience for sure)
There’s an argument to be made that by watching higher image quality versions, you’re losing on the experience. I.e. the blurriness helped the effect. Their nostalgia and your (presumably) more recent viewing are then two different watching experiences.
I didn't pick perfect examples, I picked useful ones for bounding the rough time period. Both examples are transitional.
Alien nails it like 80% of the time (I've watched it twice in the last year, in 4k on a wall-size screen, so it's fresh for me). It's an early, major example of getting it damn near perfect pretty often. Not every shot's great—like, about two-thirds of the shots of the exterior of the landing craft look like a miniature, not as glaring as a Showa-era Godzilla or anything, but you can tell—but it's still a better average than modern computer-heavy movies. It's one of the earliest that's exhibiting the potential of peak pre-CG special effects, if not nailing it all the time. But, very few movies nail it all the time, including modern ones doing the computer graphics thing.