But these are probably very basic observations.

The Alien franchise I think struggles because the titular Alien is an animal and so you do end up playing the same beats over and over. Alien and Aliens shine above all the Predator films but it's been very much diminishing returns ever since - though I am a big Alien 3 apologist.

Also, unrelated and yet surprisingly on theme, I went to watch the 20th anniversary rerelease of The Descent and can confirm it still absolutely rips.