I started to understand that game development. It is about controlling everything. Starting with the basic player score, player actions, game environment, to the game's feel. Lets take a simple example like Mario.
- You should think/know for what will happen when a player presses a button/touches device/waves the controller.
- You should know what player can do/limit with/of that actions. You should know what player go in an environment/level.
- You should know what kind of experience player goes through when all of the above happens. (Kills zombies / saves the princes / climbs a mountain / enters in a war as a soldier )
- so you should know.