Theory of 'Flow' In Games

The theory of flow was developed by Mihaly Csikszentmihalyi.

Mihaly Csikszentmihalyi - "Flow Theory"

Here is a video of Mihaly explaining the theory in his own words.

As for flow within games.

Jenova Chen Thesis - Flow in games

Jenova explains the additional theory of DDA (Dynamic Difficulty Adjustment):

Dynamic Difficulty Adjustment

Dynamic Difficulty Adjustment, also known as DDA, is a fairly straightforward and ideal 

concept in the game design field. The difficulty of a game should change dynamically 

based on its player’s skill and performance.

However, designing and implementing a DDA system is not trivial. Every so often, DDA 

systems take control away from the game designers, which potentially causes more 

problems than a linear game. Few commercial developers have implemented DDA 

systems for their games, and even fewer have shipped them. [Arey & Wells 2001]

Over all DDA is just part of the core elements of Flow, it cannot stand-alone and reach 

Flow by itself. Rather than focusing on designing a DDA system for games, designing a 

general Flow system based on all core elements will be more direct and useful for the 

game designers.

He also details the importance of expanding flow within games to allow for a more expansive experience.

Expand the Flow Zone

In order to design a game for broader audiences, the in-game experience can’t be linear 

and static. Instead, it needs to offer a wide coverage of potential experiences to fit in 

different players’ Flow Zones.

To expand a game's Flow Zone coverage, the design needs to offer a wide variety of 

gameplay experiences. From extremely simple tasks to complex problem solving, different players should always be able to find the right amount of challenges to engage during the 

Flow experience. These options of different gameplay experiences need to be obvious, so 

that when players first start the game they can easily identify the corresponding gameplay 

experience and delve into it.

-Jenova Chen