Originally Posted by Saint
Keaton really gave a cool performance as Batman, with such presence that it completely overshadowed his physical limitations.
It's funny; Keaton and Bale both said they felt like idiots wearing the absurd costumes--but ultimately Keaton just had the better solution to the problem. He basically became a sociopath when he put the thing on. He wore the suit like it didn't matter that it was ridiculous, like his character didn't even notice--where Bale's entire performance was based around the idea that he had to do something over the top to match the absurdity of the costume.
I remember Keaton once said in an interview that Jack Nicholson told him, when Keaton asked him for advice on how to approach the role, to "play the suit." I suspect he took that advice to heart.