As other repliers have stated, the film was intentionally modeled after Alien's look and feel, because Alien was such a popular success. The gritty interior sets, the 'evil' omnipresent corporation, the entire claustrophobic atmosphere and the type of musical score all add to this fact. Even the tagline was inspired by Alien's one: "Even in space the ultimate enemy is still man."
The main title sequence is very reminiscent of the Alien titles, with the title appearing backlit supported by the same type of eerie, otherworldly and somewhat unsettling music. Talking about the music, I really like this score by Jerry Goldsmith. Although similar in style and tone to Alien, it is actually very differrent from that one if you listen more carefully.
While the film borrows a lot of elements, it's still quite a good film. An interesting story, some great acting and capable directing. Peter Hyams succesfully builds the atmosphere and the tension and elevates the whole project to something worthy in its own right. Not a great movie, but quite a good, effective and entertaining one.
You said, "I love you," I said, "Wait"
I was going to say, "Take me," you said, "Go away"