Mark Ruffalo Is Bruce Banner, But Maybe Not The Hulk
And that someone else is Brandon Molale. He recently tweeted (picked up by Collider) that he had auditioned to do motion capture work as the Hulk, which is curious, but mostly because I would like to see what kind of audition that is. Does the actor just run around the room smashing things? Because I could do that. So could Mark Ruffalo for that matter. Sure, he plays unflappably cool characters, but look at those eyes. Deep down, he's a smasher.
What does this mean for theatergoers? Virtually nothing. It would be nice to know that one actor was portraying both iterations of the character, but I don't foresee anyone leaning over to their date during a Hulk rampage and mumbling, "This is bullshit. That's not Ruffalo." My advice is to forget everything you just read and enjoy the movie.