Back in the day, Starlog was hyping this film as an almost sequel to Alien. With the popularity of the film, folks were ravenous to see more chest bursters in action. That said this has nothing to do with the original other than stealing just about every single plot point.
Instead of space, this film goes to a more terrain yet not less remote location: an oil rig packed with folks like Chad Everett (TV's Medical Center, Mulholland Drive, Airplane II) as our mustachioed hero, Jennifer Warren (Mutant, Slap Shot) as his love interest and fellow rig worker, Joseph Bottom (The Black Hole) as the villain, Rocke Tarkington (Ice Pirates) and Paul Larsson (The Blaster from Mad Max: Beyond Thunderdome!). It's worth noting that every conversation the characters have pre-alien is about hooking up. They're far from the mainland and feeling the urge to just get it on because all the drilling is getting them hot and bothered.
I hesitate to even write the plot to this, as I could just write the plot for Alien: crew finds eggs, someone goofs about and pays the price, the monster starts stalking the ship, hijinks ensue. Again this film is hypersexualized, as one of the first monster attacks is more rape than attack. And there's always a KY jelly like substance leaking out of everything. It's also pretty bleak the raped crew member dies after she gives birth to a full-sized alien and just about everyone dies pretty horribly if off-camera, as this was still broadcast TV.
There's also one well-done section of the film that explains that whatever the creature is, it predates the Biblical Flood and has lived beneath the ice for millions of years very Lovecraftian themes that are never followed up on, sadly. Plus, being the '80s, there's a subplot about the oil company Zortron and how they may want the creature and eggs more than the oil (again, a plot point taken straight from Alien) and some character work about cheating spouses.
The actual creature suit is pretty nice and holds up well to being in the light. It was created by James Cummins, who also contributed to House, DeepStar Six (I'll be getting to that one), Enemy Mine and The Beast Within. It's very Giger-influenced to the point that many people incorrectly report that Giger worked on it. That said, it's pretty strange to see an alien climb a ladder!
For all the exposition, set-up and character development, this movie ends just when it seems like it's picking up steam. Who knew all it takes is a flare gun to defeat an alien? It certainly surprised me! The Intruder Within got to the party early, but it's not the best of movies filled with blocked off TV movie direction, too dark camera-work and a short running time. That said it still has some charm and you can find worse ways to spend 100 minutes.
Review by Sam Panico from the Internet Movie Database.