Game mechanics are constructs of rules or methods designed for interaction with the game state, thus providing gameplay. All games use mechanics; however, theories and styles differ as to their ultimate importance to the game.
This means that their importance in the game industry is great as the making of game mechanics and game logic can decide what genre the game is, you can into to great or little depth depending on how big the game is. For mine, a simple game, I will use it for only a few things; Taking damage, Dealing damage, Movement and Enemy movement.
A great deal of people use flowcharts to represent their mechanics and game logic, I will also attempt to do this for my level 2 game to show you an example of how it could be done. The following two pictures are screenshots are taken of flowcharts I made for the process of taking and dealing damage both of which will be used in my Level 2 game.