Wolfenstein was far inferior, technologically. A flat, square blocky map, without any way to look up or down, or any height variation at all. The maps were actually defined as ASCII grids with different characters defining where it was a wall or open space, secret door, etc.

UU had irregularly shaped rooms and hallways, inclines and declines, the ability to be at two highets depending on where you are on the map (bridges over water you can swim under) which even DOOM, the successor in engine technology to Wolfenstein 3D didn't support, etc.