I was watching the documentary on the film Alien from the Alien Quad set as well as listened to the audio commentary of the film and I found out something interesting: On the movie box it shows that the story and screenplay was written by Dan O'Bannon and Ronald Shusett. However, according to Shusett, David Giler and Walter Hill actually made a lot of changes to the screenplay. The creation of Ash as an android for instance was one of them. According to the documentary Shusett thought Giler and Hill adding in Ash was brilliant, while O'Bannon in the audio commentary was a waste of time. I actually looked through the original script which was also on the Quad set and found it to be different from what was filmed somewhat and wasnt as good, which I found ironic that O'Bannon and Shusett felt each revision got worse, which suggests to me that Giler and Hill played a bigger part in the final product then initially thought. I guess my question is: How much did Giler and Hill actually contribute to the script and why are their names never mentioned when talking about the Alien series since it seems like they played a much bigger part than they are often given credit for? Its also important to point out that the great Alan Ladd played a big part in getting this film greenlit and nobody should ever forget his role in getting Star Wars greenlit.