Successfully complete the indicated task to unlock the corresponding
challenge:

Challenge 1: Successfully complete Act 1 on the Normal or higher difficulty.
Challenge 2: Successfully complete Act 2 on the Normal or higher difficulty.
Challenge 3: Successfully complete Act 3 on the Normal or higher difficulty.
Challenge 4: Successfully complete Act 4 on the Normal or higher difficulty.
Challenge 5: Successfully complete Act 5 on the Normal or higher difficulty.
Challenge 6: Successfully complete all five challenges.