[ibnroberttuta]

This is a textbook, ZMP derivative type controller.

ZMP doesn't necessarily require absolute maps of the environment, but generally is more of a predict and optimize for safety type affair, and Atlas i'd imagine does that both very quickly, and a bit smarter leg reaction movements.

The linked video is more akin to elementary central pattern generation, which is a very understudied field, but their is more advanced research on the topic from pre 2010 if you are curious. Interest seems to have dropped off unfortunately in the really cool stuff since then, but you can find it with moderate ease.