Ashley Cornall’s review:
The opening section of Alien reminded me a lot of a Gothic murder mystery - slow moving, rolling fog over silhouetted hills, unfriendly (usually silent) locals, and some dark secret lingering beyond the knowledge of the main characters.
Even past that point of discovery, it becomes something similar to an old-fashioned locked-room mystery, except that instead of trying to find out WHO is the murderer, we're trying to find out WHERE they are.
Maybe that's why it holds up so well thirty-something years later. It relies a lot less on gore or shocks (although that's what most people reference when they talk about it), and a lot more about that creeping unease of what we don't know and what we can't see.