I've completed act I on normal, but i wanted to go back and kill Butcher again, but it doesn't seem possible. I go back to the quest and the dungeon but there's no entrance to Halls of Agony lvl 3, only the waypoint, the way up to lvl 1 and highlands passage.
Remake the game you cant kill a boss more then once in a game since you obv already killed it. So remake the game then head back to the boss and kill him again..