Major Project Hail Mary spoilers ahead! 🛑 If you haven't seen the book-to-screen adaptation of Andy Weir's Project Hail Mary, consider yourself warned!It's been months since Project Hail Mary made its theatrical debut on the 2026 movie schedule, and I have yet to tire of watching the movie or learning new things about it (like Stratt's tattoo or how they made the astrophage. I especially love learning behind-the-scenes facts about Project Hail Mary that impact how I watch the movie the next time I inevitably do. If you're in the same boat, good, good, good, because you'll want to pay attention to two specific scenes the next time you watch Project Hail Mary. Ryan Gosling's reactions in both of them are the actor's genuine responses. The topic of Gosling's reactions came up a couple of times on the Blu-ray commentary featuring Project Hail Mary directors Phil Lord and Christopher Miller.(Image credit: Amazon MGM Movies)When Grace And Rocky Are Imitating Each OtherDuring the scene where Grace is meeting Rocky for the second time, just after he gets scared, he realizes Rocky is mimicking him. He then proceeds to do a series of funny poses, and Rocky imitates them. It's one of the first of numerous adorable and funny moments between the duo. Some of what we see of Rocky in this scene is CG, according to the filmmakers, while other bits are shot with the Rocky puppet. From what Lord said on the commentary, the puppet team didn't know what pose Gosling would do until he did it, and then they had to figure out how to get Rocky to strike the same pose.We did this live on the day, and we told Ryan, we had an earwig to him, making suggestions about what dances to do and moves to try. The puppet team did not know what he was going to do, so they had to figure it out on the fly, and it created a really lovely effect. That's a fun fact all by itself, and as he notes, it led to some of Ryan Gosling's amused expressions as he watched the puppet team do their thing. As Miller put it:So some of Ryan's reactions are of him actually absolutely delighted by the puppet team trying to copy what he was doing.Ryan Gosling being delighted by what's happening in front of him applies to the other scene I want to talk about. This one has to do with the end, so if you ignored the spoiler warning 🛑 before and haven't seen the movie, consider yourself re-warned! When Grace Is Looking At The Eridian StudentsI started the other scene with a fun fact, so I may as well do the same here. When Lord and Miller were discussing the final scene in the movie, where Grace is about to begin a teaching session, and it cuts to a classroom full of pint-size Eridians, they referred to the children as the "muppet babies," which I just think is so stinkin' cute. It's also relevant to the quote from Phil Lord, where he talks about how Ryan Gosling's reaction to the classroom was actually his genuine smile at seeing Lord, Miller and the crew dancing around in front of him:The people playing the muppet babies on the day were you, me and the crew dancing around and trying to do anything to make him smile.As they explained in the commentary, some of the "muppet babies" that we see in the classroom scene are puppets, while others are CG. The smile on Gosling's face, apparently, is 100% practical effect.It's such a great final moment of the film, and I love knowing there's a bit of a real reaction from Ryan Gosling in that final shot of him. I'll close this out with a fun little BTS fact about the ending of the movie, which was also shared on the commentary. The reason the sand on the beach is like rocks is that Rocky got the scale of the grains of sand wrong when he attempted to recreate the beach for Grace. Doesn't seem like Grace minds, though. You can listen to Phil Lord's full commentary for Project Hail Mary on the Blu-ray and 4k UHD edition. I don't see anything about a commentary on the back of the DVD packaging, so it might not be available on that edition.