Will surfaces have different levels of friction, such as ice being slippery and mud being sticky, and how will that affect your character movement?

All these design questions. I don't know if it will have a direct effect as far as character movement. Again, if I think about the level of detail that we put into things, I would assume there would be some knock-on effect, right? But how minimal or how drastic is it? Is it an element that we play into on design? I'm honestly not sure yet.