As Jekyll? Perhaps, although I would perhaps blame that on his tough-guy persona in films before that, but his performance really shines as Hyde. I don't doubt that Tracy drew his "change" from his own bouts with alcoholism. It's probably the reason why he eschewed a good opinion about the performance years later—it hit too close to home.

I know a big complaint about the film from monster fans is the minimalist make-up and the unbelievability that no one recognizes the two, but if you look at him as Jekyll, and then look at him later on in the film as Hyde, the psychological effect of going from a good man who can do no wrong to pure evil really distorts his expressions and general looks and he really does look different. It's a great example, to me, of not having too much makeup and letting the actor's expressions do the work. Could you imagine how ridiculous Spence would have looked with WIZARD OF OZ-type rubber appliances all over his face?