Alien is the type of classic film that our current generation will never experience first hand. It's a slow paced dynamic feature that blends sci-fi and horror into a perfect hybrid masterpiece of late 70s cinema. Films today concentrate too much on the CGI money shot instead of building a solid back story and character driven dialogue.
As Ridley Scott's first major cinematic excursion, Alien struck a note that no one else had ever hit. For the time, it was an extremely adventurous piece of work that is absolutely unsettling to this very day. Alien should be considered the standard by which all sci-fi/horror films are based. Instead, the film has been used as a template for numerous low budget knock offs.
Many things still make Alien an absolute cinematic feat. This is attributed to the details that modern cinema is lacking: a strong director with vision, a skilled cast of varying experience, and a unique horror story that will terrify the viewer to their very core. Have you seen anything in the last 10 years that has done that? Probably not. If you've never seen it, take the time and watch this movie. It is a modern classic.