Here's screenwriter Dan O'Bannon's original concept art for the creature in Ridley Scott's Alien. Other Alien/Aliens concept art floating around online includes H.R. Giger's early face-hugger drawings and the heavy loader design that James Cameron rejected.
This is a bunch of concept art and rare images we came across on the web, some of which appears to be screenshots from the rare Alien/Aliens laserdisc. None of it is new, but it's all new to us. (You can view it in non-gallery format here.) Check out more Alien-related goodness at these links, and also check out H.R. Giger's website. [When is evil cool? and Skiffy]
Concept artist Ron Cobb's original alien design - he worked on the film before H.R. Giger came on board.
The original alien's articulated jaw - note that the alien actually had a human skull in its forehead, which isn't really visible in the film.
Another view of that weird skull-forehead thing.
H.R. Giger's original facehugger concept art.
H.R. Giger alien concept art!
H.R. Giger alien concept art!
H.R. Giger alien concept art!
H.R. Giger alien concept art!
Moebius' concept art for human uniforms
Ron Cobb concept art
The Nostromo cockpit concept art by Ron Cobb, which became the actual blueprints.
More Cobb concept art.
More concept art.
More Cobb concept art.
More Cobb concept art.
Early concept art for the ship with the alien eggs in it.
Ridley Scott drew his own storyboards for the film.
More Ridley Scott storyboard art.
James Cameron's painting of the alien planet.
James Cameron's concept art for the alien egg sacs
James Cameron's alien queen concept art.
Syd Mead's concept art for the heavy loader, which Cameron rejected.