Before starting a game, it is essential to create a Game Design Document (GDD). This document serves as a groundwork for the game you will be making. In all, 99% of the time when we start making a game, we lose track of the features planned for it and deviate from the core game experience. So, it is always recommended to have a GDD in place in order to keep focus. A GDD consists of the following things:
- Gameplay mechanics
- Story (if any)
- Level design
- Sound and music
- UI planning and game controls
You can read more about the Game Design Document by navigating to the following link: