The theory of game is we must know that we want to make the game how? Such as the adventure game, the game of war, the city game, and the game plan etc. So, when we know that we will write games. We must build up a scene and Character. Sounds in the game. How to game that do steps to cut scenes. In the design general of the game had 2 type is 2D with 3D.
The programs we use to create games in general, and easy to write is programs Unity.