The teaser trailer for Buried was pretty much perfect for advertising the film for what it was, I don't see the need for revealing anything more. But, I get the feeling Lionsgate released this trailer as a way of placating fans who wanted actual shots from the film.
It looks like Nathan Fillion might be playing a superhero afterall. After being considered for roles in Green Lantern, and Captain America,Fillion (most remembered as Malcolm Reynolds in the cult-hit Firefly) is reportedly in final negotiations to play Dr. Hank Pym in the new Avengers film. It hasn't been stated whether Pym would be Ant-man in the film, or just a S.H.I.E.L.D. scientist, but we're holding out hope.