Star Wars: The Last Jedi - 39 Things We Learned From The Director's Commentary

8. AT-M6s

Johnson states that the AT-AT walkers are one of his favourite designs in all of movie history, so he knew he wanted to do an evolution of the design. He kept coming up with different ideas, but all of them seemed too clever until they eventually settled on honing in on the brute strength aspect, like gorillas.

The Millennium Falcon chase through the caverns of Crait, meanwhile, is actually a homage to the original Star Tours ride. The first few times Chewie knocked the Porg out of the way it looked like he was just punching it, so they had to make it clear he was knocking it out of the way to press a specific button, because you can't attack a poor little Porg.