One of the more densely layered visual sequences in Guardians of the Galaxy comes when Star Lord, Groot, Drax, Gamora and Rocket visit Benicio Del Toro's character The Collector during their sojourn to Knowhere. His collection is filled to the brim with so many easter eggs and callbacks to the Marvel universe (not to mention one of director James Gunn's prior films, Slither) you need several viewings to process all of it. If you've seen the end credits tag you'll know that The Collector even has a prized (if marginalized) Marvel character in his possession.
But of course the aesthetic choices you see in the film didn't just arrive in their current form. A considerable amount of work was done testing different concepts and looks - some of them departing radically from the finished design - before the creative team settled on the environment you see onscreen in the film. Hit the jump for the Guardians of the Galaxy Collector concept art. The film is still in theaters. See it again.
You can find more concept work on the site of artist Richard Anderson (via CBM):