Trivia: There are two scenes after the movie finishes. The first one is of a young Groot dancing, with Drax trying to catch him out. The second scene comes right at the very end - Howard the Duck makes a cameo appearance with The Collector. Howard can also be seen faintly in the background of the scene with The Collector during the movie.
Trivia: The studio originally wanted Amanda Seyfried for the role of Gamora. But despite loving the screenplay, Seyfried feared that given the obscure nature of the characters and the inherent weirdness of the script, the movie would bomb at the box office. She didn't want to be in the only MCU film to fail commercially. The film ended up going on to be a massive success, and Seyfried has expressed some regret over the decision.
Trivia: Dave Bautista was driving to the gym when he got the call from his manager and agent to inform him he got the role of Drax. He was informed by being told "Congratulations, Mr. Drax." He claims that upon being informed, he broke down crying hysterically and had to go home, because he was so happy and awe-struck by landing the role.
Trivia: Troma Films creator Lloyd Kaufman has a brief cameo during the prison sequence. He is seen among other inmates briefly looking over a railing. "Guardians" director James Gunn got his start with Troma and is good friends with Kaufman, hence the cameo.
Trivia: When Quill has been arrested on Xandar and his name and crimes are being reviewed, his alias is shown on the view screen but it appears as "space-lord" and not "star-lord." As ever, they've got his name wrong.