Dynamic Difficulty in Video Games Matthew Carlson

Initial Motivations “It sounds like the "dynamic difficulty" tries to make it so it's easier when you're doing poorly and harder when you're doing well. This sounds like an arbitrary way to eliminate all sense of accomplishment from a game. Isn't part of the fun having difficulty, and then overcoming it... This idea would really diminish the significance of winning or losing.” --Joystiq.com What's wrong with prior implementations?

Research What methods are currently used? http://jenovachen.com/flowingames/designfig.htm http://onlyagame.typepad.com/only_a_game/2005/11/riddles_of_diff.html

Research What is the problem with this method?

What is different about this approach? Desired difficulty depends on the player: Player A: Player B: The key to finding the appropriate difficulty is to determine what type of player is currently playing.

-Let the player decide difficulty How do we determine what the player wants? -Let the player decide difficulty

So, what exactly does this project do? Changing the game based on player's performance:

How do we determine if the player is frustrated? -Moving in circles -Shooting erratically into walls -Player harming themselves -Deaths -Time to complete -% of monsters killed, goals completed, secrets found -Damage taken -Total shots fired, hit (for, against)

What did I find? Difference between static and dynamic settings was relatively small.

What did I find? cont. Interesting Rules: Rule 1: Decision Tree: monsters_killed > 0.846154 : 4 (6.0/1.0) monsters_killed <= 0.846154 : | damage_taken <= 785 : 2 (2.0/1.0) | damage_taken > 785 : 5 (4.0) Rule 2: damage_taken <= 785 : | time <= 1385.6 : 2 (3.0) | time > 1385.6 : 4 (4.0/1.0) damage_taken > 785 : | monsters_killed <= 0.846154 : 5 (4.0) | monsters_killed > 0.846154 : 4 (5.0)

What did I find? cont. Interesting Rules: Rule 3: Decision Tree: secrets_found > 0 : Completed (23.0) secrets_found <= 0 : | level = 0.000000: Completed (4.0) | level = 2.000000: Completed (0.0) | level = 3.000000: Completed (0.0) | level = 5.000000: Completed (7.0) | level = 6.000000: Quit (1.0) | level = 7.000000: Completed (3.0/1.0) | level = 1.000000: | | time <= 163.6 : Quit (2.0) | | time > 163.6 : Completed (7.0) | level = 4.000000: | | time <= 427.4 : Quit (3.0) | | time > 427.4 : Completed (4.0) These results indicate that a person is frustrated by a lack of success more so than a temporary failure.