Game Mechanics, Dynamics and Aesthetics

What is the difference between Game Mechanics,  Game Dynamics and Game Aesthetics?

Game Mechanics are the rules of the game.

Game Dynamics is the direction or resulting effect of the Game Mechanics.

Game Aesthetics is the experience of the player based on the Game Dynamics.

For example,  certain game mechanics might reward a player with power ups including shields.
The resulting dynamics is that the player is invincible and can defeat enemies easily (positive feedback loop). The aesthtics is the feeling of satisfaction and accomplishment on defeating the enemies.

Certain schools of thought in Game Design advocate starting with Aesthetics then work backwards to Dynamics then back to Mechanics. For example, first ask yourself, what sort of Player experience/feeling do I want the player to have?  Is it accomplishment, anger, fear, greed, friendliness?  Then find out what sort of Dynamics can bring that feeling/experience? Then determine what sort of mechanics can bring about those Dynamics.

So, designing game is designing experience.

A formal definition is:

Mechanics describes the particular components of the game, at the level of data representation and algorithms.
Dynamics describes the run-time behavior of the mechanics acting on player inputs and each othersí outputs over time.
Aesthetics describes the desirable emotional responses evoked in the player, when she interacts with the game system. 

MDA : A Formal Approach to Game Design and Game Research