Level design is pseudo open world, but player movement is limited from heading into empty areas, essentially map layout is more like a big spider web spreading out from the the guardian sanctum with 4 or 5 major paths that each lead to one or two major boss areas. When it comes down to progressing towards a boss fight the level design becomes a lot more narrow with the player traversing between small open areas where a fight with smaller enemies would happen. (ala string of pearls).