Tobar said:
I went out of my way to find a copy of the theatrical version of Alien because I kept hearing about how the director's cut wasn't actually a director's cut and how it was actually shorter than the theatrical version and that the only new thing about it was a quick shot of an alien egg hatching.
Here's the rundown on that.
The 1979 cut of Alien is Ridley Scott's preferred version, so it's his "director's cut."
In the early 2000s, Fox was looking to create extended versions of all the Alien movies for the Quadrilogy box set.
Scott found out and offered to recut the movie himself (or they asked him, I can't remember). So he did, and the studio called it a "Director's Cut" since he actually worked on it.
Scott sees the 2003 "Director's Cut" as an alternate version that's cut more to modern sensibilities - a lot of small trims are made to make the movie move by a little quicker, but it's not noticeable unless you're really familiar with the movie (the comment Dallas makes about Ash being a last-minute replacement is cut, for instance).
He also added in a few deleted scenes - Ripley finding Dallas being turned into an egg and killing him with a flamethrower, Ripley arguing with the rest of the crew just after Kane is brought aboard against her orders, a clear shot of the Alien in the scene where Brett gets killed (which is the main thing I dislike about the 2003 cut), etc. And, yes, Kane and the egg was recut slightly IIRC.
Overall, with stuff being cut out and stuff being extended, the 2003 cut clocks in at roughly one minute shorter than the 1979 theatrical cut.
So there you have it - it's a very subtle alternate cut with a few extensions and a few trims, but nothing Earth-shattering. I still prefer the 1979 cut, as does Ridley Scott himself, but aside from that one shot of the Alien in Brett's death scene, there's nothing wrong with it, either.