Dull but playable.
AoW, Three Faces of Evil, one fight with Darkness-as-Darkness took most of a session for a short combat because the PCs AND THE MONSTERS spent most of the time stumbling around in the darkness, moving at half, making balance checks for rough flooring in the dark, 50% miss chance, groping around in the dark to find things (with 50% miss chance) ... we used the Listen Check/d8 method for locomotion as well ... we were also using "Hampered Movement" for "poor visibility" so the GM was calling for Balance checks unless we moved at 1/4 speed ...
Nobody, including the GM, had much fun with it. We decided, if it was that much of a total PITA to do anything in Darkness, we'd have to cover everything in Darkness at every opportunity and funnel the badguys into the lighted areas where we were. Then he'd have to do the same thing. Then every combat from there on out would be an utter nightmare of constant checks, random movement, and 5' steps.
--fje