This poster is freaking fantastic. It has a great feel to it. I was thinking that this is the way Disney should have gone with the promotion of their groundbreaking CGI video game movie from 1982. Be mysterious with it, low key... instead of the "computerized Fantasia" they pushed. Although, thinking about it, the poster feels a bit too 70's, a vibe that would probably have given the public the idea that the movie was dated even before release:
Still though, a great poster, designed by Mark Welser. You can pick up a print over at Etsy.
For more information on Disney's seminal Tron, consult your local Dot Eaters article.