Last week in CS4067 we discussed udology and narratology. Basically if the rules of a game are simple then the game is Paidea ('play') and if the rules are complex then the game is Ludus ('game'). An example of Paidea would be the game Tetris, which focuses on the enjoyment of the player rather that achieving a specific victory condition. An example of Ludus would be 'Command and Conquer 3' where the player is giving very specific conditions needed for victory before each mission, e.g one mission might be to capture a certain enemy building whilst another mission could be to destroy all enemy units.

Both theories are useful for describing games but I personally think most games don't fall into one single category even Tetris which is considered a good example of Paidea it could be argued that it contains elements of Ludus i.e. Tetris has a two player mode where the conditions for victory are to outlast your opponent.