Peter Quill: You're like Mary Poppins.
Yondu: Was he cool?
Peter Quill: [Pause] Yeah, he was cool.
The wound and blood on the left side of Starlord's face disappears at the end of the film.
When Nebula and Gamora come across the skulls, one of the skulls has a horse-like shape to it. This is a reference to the character Beta Ray Bill, who in the comics was one of few characters worthy enough to lift Thor's hammer. Or possibly Kymellians - horse headed aliens closely associated with the the preteen Marvel team, Power Pack.