I think the original RED may have been one of those very unique comic-based movies where absolutely nobody cared that it departed from the source material quite a bit. For a comic, it was admittedly tense and cinematic, but totally predictable; turning it into a comedy based on the idea that retired people kicking ass is inherently amusing even when true was a smart call.
The sequel has even less to do with the source (and this may be even freer to be its own thing without being tied to any of the book's beats), by the looks of it, but there's more of everything that worked the first time: crazier Malkovich, more deadpan Mirren and the addition of Anthony Hopkins as a guy with no concept of the passage of time who literally does not know he's old.
And it's the director of Galaxy Quest, a sacred entry in the nerd canon if ever there were one.
Trailer and more character one-sheets after the jump. Note to rival marketing types - notice how tinting your posters all one color makes photoshopping far more forgivable?