The 'awesome mix' cassette tape shows part of a distinctive logo under the label from a TDK cassette tape type II , 'CDing 2' . This cassette tape first came out in 1993 , yet the start of the film is 1988.
In the Kyln control tower. Drax is stated to be "Completely literal. Metaphors will go over his head." Drax confirms this. While planning the assault on Ronan, Drax uses the metaphor, "I think of the Sakaarans as paper people."
When Peter is escaping Korath in his ship on Morag and the ship is upside down, he smacks into the windshield. In this shot, he has no gloves on, where moments before he did. In the next shot, when he's reaching to grab the ship's controls, he has his gloves on again, and they remain on for the remainder of the scene.
At the Kyln, when the Guardians are dealing with the Monstrous Inmate, Gamora is behind Quill when she speaks. When it cuts to a wide shot, and all the shots that follow, Gamora has disappeared. We don't see her leave.
As Star Lord is entering the temple to steal the orb he grabs and picks up one of the rat creatures. In the close up shot that follows he uses the rat as a microphone. In the next long shot he has no rat, next close up shot the rat is back. This repeats again.
The human body is a pressurized system and can easily withstand the vacuum of space. It will not boil. This is a common misconception that has been shown to be false many times, most notably with the crew of the Soyuz 11 spacecraft who are the only people that have ever died of space exposure. The capillaries near the surface of the skin will often burst and some blood may trickle out of orifices such as the eyes and nose, but the main portion of the circulatory system, not to mention the internal organs, will remain perfectly intact. Due to the extreme cold of space, it is very possible for ice crystals to form from the ambient moisture on the skin as well. However, this would take quite some time since, in a vacuum, there is no medium to transfer the heat energy that would be required to turn water to ice.
When Rocket is explaining his Prison Escape Plan and Groot goes to get the battery mounted on the wall, Groot's food tray disappears from his right hand as it passes behind Peter's head. However, you can see that his body leans to the right as he passes behind Peter in the frame and a clinking noise can be heard, hinting that he dropped the food tray off onto the table.
In a perfect a vacuum, no sound can be heard; but when Peter is rescuing Gamora the sound of his boots is heard, as well as other things. This is due to the fact that Peter and Gamora are still well within the gravity well of Knowhere and so, still surrounded by the faintest of atmospheres.
When Quill is captured by the Nova Corp and he is in front of the window being reviewed, on the text on the window to the left they list his alias as "Space Lord" not "Star Lord".
This is just a continuation of the running gag throughout the film, where no-one can remember Quill's 'codename'.
During the final battle, Gamora explains that Ronan will secure himself in an impenetrable safe room. She must destroy its power source to allow the other Guardians access. However, once she does this, she simply shoots a hole through the floor with a rifle and joins them in the "impenetrable" safe room.
When Quill dives through the air to catch the Infinity Stone, he's reaching for it with his right hand, but then, as it starts to transform him, it's clutched in his left. What is hard to see is that he switches hands as he writhes on the ground.
When Gamora is floating in space, Star Lord flies out to give her the helmet. Shortly after, Yondu brings them onto the ship, Gamora and the Star Lord don't have the helmet. However Star Lord's helmet retracts to a small device behind his ear. After he puts it on Gamora, it just retracts back to its smaller form.
While they are trying to hold off Ronan's ship, Rocket tells the NovaCorp that the city has been evacuated, but after Ronan's ship crashes to the surface there's a substantial crowd forming around them.