In a recent interview with CinemaBlend, Ruffalo talked about his performance in Ragnarok, which is pretty evenly split between Hulk and Banner. As he explained, that task was significantly less daunting than it would've been in years past, thanks to the new advancements in motion capture technology.
"The technology is now at a place where you can really do a performance inside these characters." Ruffalo explained/ "And you can do it on set! Before I'd have to do all this stuff on my own in a motion-capture volume, without having the actor there. But now I get to act it all, and be on set with Chris [Hemsworth], and do these scenes with him. And so it becomes a lot more do-able and accessible."
As he explained, the ability to act out the scenes on-set was helpful - although it didn't completely alleviate the process.
"It's still daunting, it's still really hard to do." Ruffalo explained. "I have a love/hate relationship with it... but it works! It's exciting when you see it."
Judging by the early response to Thor: Ragnarok, it sounds like Ruffalo's new outlook on his performance has paid off. The film debuted with a 100% rating on Rotten Tomatoes, and has since garnered even more positive reviews. And it certainly won't be the last that audiences see of the Hulk, with Marvel planning to tell an epic three-part storyline between Ragnarok and the next two Avengers films.
Thor: Ragnarok lands in theaters on November 3rd.