I've spent minutes deliberating dialogue options. I haven't seen all the ending permutations (and I don't think I want to), but it seems like the end state of the world is vastly affected by choices in game.
There are times when you beat a boss and the cutscene gives you a choice between sticking around and instancing to another area. If you choose to stay, you can often loot the boss room for stuff. Example: When you go to Bald Mountain and defeat Imlerith, you can loot a Magic Acorn from his body. When consumed, gives you +2 ability points.
Um... The big spider, The witches, Vicar Amelia, and all of the ones in between? I've also cleared the first Chalice Dungeon and am one level into another.
EDIT: I've died probably 25 times in the village at this point, which is easily twice as much as any other area so far.
There is a cheese strategy for the hunters that leash together. Aggro them and then haul ass back to the Lamp. They will get stuck in the doorway, where you can just attack them through the wall until they die.
Just beat the game right now. The bosses I thought were most challenging were surprisingly the ones I beat on my first try. Overall, this game is more inspired in enemy and level design than dark souls 2, though I was never one that complained about the quality of that game.
People often think the "souls" franchise of games is its own genre, but in reality, this is a boss rush in the same vein as megaman or metal gear solid.
You can actually get the game to loop spawns after you get a chest in the room he's in (and around it) at 4:21. It's called the infinite chest/spinmetal run. It's a lot faster than the traditional rocketyard chest run (which this video shows).