All games start off as just ideas from either a company or individuals.  Next in the pre production stage the team making the game have to discuss the storyline, plot, characters,game goals,level designs,and gameplay mechanics. The pre production is based on the limitations of what the game is based on. Then they make visual representations of how a part of the game would and should look like. Then you get a story line for your game. You also make storyboards and use these to show the most important aspects of the game so that the programmers can know more about what they have to script. Then list out what the player is capable to do and how to adapt that to a certain button on a controller or keyboard and mouse. Next is the post production stage which is when all the coding and art designing is done. The game is in alpha stage and is tested for bugs and find out ways to make the game better. Then after that is sorted out a beta version is made where it is tested again to see if the bugs and other issues are fixed from alpha. They document any issues with what is in the beta. If the game is for console you have to go through a stage to make sure the game meets the criteria for the buttons of a controller. After that they make a final version of the game and if for console it is game tested one more time but the consoles respected parties.