Marvel Studios finally released the first trailer for Avengers: Infinity War, and it's revealed a lot about the plot of the film and how the characters involved will interact. However, this is not the only footage out there that the company has released thus far. Over the summer, Marvel revealed exclusive footage from Infinity War at Comic-Con International in San Diego and the D23 Expo, and while most of it is seen in the new trailer, there are still a few scenes missing.
How Thor Meets the Guardians
At the end of the trailer, we see Thor interacting with the Guardians of the Galaxy for the first time. However, the SDCC/D23 version of the trailer provides a much more in depth explanation as to how everyone meets. In this version, the Guardians discover Thor's body drifting out in space. He hits the windshield and Rocket tells Peter Quill to use the wipers, as if Thor were a bug.
This is obviously what happens to Thor following the events of Ragnarok, where the Asgardian refugees are intercepted by Thanos and his followers. The Guardians bring him into the Milano and Mantis uses her power to wake him up. This is then when we get the scene at the end of the official trailer where Thor asks the group who they are. It also explains where the Odinson is during the trailer's opening monologue.
Something that is worth noting is the fact that the SDCC/D23 version of the trailer actually didn't have Thor missing an eye. This was likely done to avoid spoilers from the end of Thor: Ragnarok, and now that the film is out, the real version can be shown.
The official trailer seems to put a lot of focus on the original Avengers team, while other secondary and tertiary characters revolve around them. The big moment is when Captain America gathers the heroes from the previous films in one big slow motion run toward the camera, but what about everyone else? If this is a crossover film, where is all the crossover?
The SDCC/D23 footage has a lot more of that going on, with different characters from other films across the Marvel Cinematic Universe appearing in the same shot. They aren't especially important scenes, but seeing these characters side-by-side for the first time does help to enhance the connectivity of the universe.
In the footage left out of the official trailer, we see Peter Quill and Stephen Strange in battle with Thanos, with Quill jumping across magical platforms that Strange has apparently created. Another scene has the Guardians and the Avengers in one place with Quill, Drax and Mantis standing beside Iron Man and Spider-Man.