Difficulty curve - Is there such a thing as the ideal curve?

The construction of a difficulty curve is one of the key tasks in level design.

If the difficulty is poorly tuned, the game can become either impossible or boring. We all have memories of difficulty peaks in game that led to the distant throw of a pad or a mouse. on the contrary, how many games have we stopped playing because there was no more challenge ?

Does that mean a difficulty curve should always be smoothly upward ? Of course not. There is no ideal difficulty curve. Recent triple-A titles have shown that totally different approaches are quite valid.

For its shooting sequences Uncharted - Drake's Fortune follows a classical approach to difficulty curve construction . It is built like a staircase. Difficulty is flat, then it increased significantly and remains flat for a while until the next step. The introduction of a new category of enemies or the total number of them in a given firefight often trigger such steps.

Gears of War 2 or FEAR 2 follow a different approach. Their difficulty curve is basically flat. There are a few difficulty peaks from time to time but those are exceptionnal. Of course, if you change the difficulty setting, the game's experience will change but the level design does not.

The designers of FEAR 2 and GoW 2 are not using the difficulty curve to "glue" the player to their game machine. Epic designers constantly renew the player's experience while Monolith's designers use storytelling to achieve the same result: Getting the player hooked to the end of the game.

I draw two lessons from my analysis:

1. There is no single approach to the construction of the difficulty curve
   
2. The profile of the difficulty curve in the game should be planned as one of the components that build a player's experience and should not be an afterthough.