Notes: The game design document

The game design document

Before you can begin actually building the game, there must be a clear understanding between all parties about exactly what is being created. All of the following must be able to mesh seamlessly (both in timing and in content) to create a strong game:

The designers and writers need to be able to flesh out levels, storylines, dialogue, etc.
The artists need to be able to understand the look and feel of the works they are to create, and the scope of the art assets required.
Similarly, the actors and musicians need to be able to record their scores and voice overs.
The sales and marketing team needs to understand the theme and feel of the game, and to understand what will be available for key market deadlines (e.g. will demos be available for major conventions, can the product ship in time for Christmas, can it be timed to release with related events, can it beat its competitors to market, etc).
The programmers/developers need to be able to develop the detailed technical requirements, and to design the actual software in accordance with the designers view.

The goal of the game design document is to describe everything clearly enough to guarantee all the different participants can work on their part of the game without fear of confusion or misunderstanding.

A game design document might be structured something like this:

Concept or vision

A clear, concise description of the game and the user experience: what genre/style is the game? where is it set? what is original or unique or unusual about it?
Market analysis
Here one details why the game should be successful and backs that up with supporting research.
- what target audiences and market(s) have been chosen, and why?
- what platform(s) have been chosen, and why?
- what are the system requirements, and why have those limits been chosen?
- which games are the primary competitors for this game, and how does this game stack up against them (pros and cons)
- based on all the above, what are the revenue predictions (with justification)?
Core gameplay
Describe how the game play functions: how the game\ mechanics work, how objects interact, the controls and interface, what the game rules are, how you win or lose, etc.
Describe the storyline, goals and milestones for the player This will likely include a very short synopsis, plus a detailed storyline, plots and subplots, and any supporting backstory or relevant history.
Describe the key playable characters (traits, abilities, behaviour, guidelines, etc)
Describe the key NPCs (non-playable characters) (traits, abilities, behaviour, guidelines, etc)
Describe the key levels of your game's universe (travel, locations, scale, physics, culture, etc)
Describe any supporting tools for configuration or modding (level editors, model viewers, etc).
60 seconds of gameplay
Here the goal is to crystallize the vision of the game, by describing (in detail) roughly 60 seconds of typical gameplay -- all the user actions and the game responses.
Asset list
a list of all the sound effects needed
a list of all the voice-overs needed
a list of all the music needed
a list of all the cut scenes needed
a list of all the scenarios needed
a list of all the animations needed
a list of all the models needed
a list of all the player and non-player characters needed
a list of all the possible AI behaviours
a list of all the different physical event types that must be handled
a list of all the possible character actions that must be handled
a list of all the possible player actions/choices that must be handled
a list of all the item types that must be created (weapons, equipment, ...?)
... etc. etc. etc. ...
Technical specifications
Describe any technical risks associated with the project, and the plans for avoiding/mitigating them.
Detail the core software development tasks, plus the platforms, tools, and resources required for development (including support tools and software).
Describe the game engine/physics in detail: features, specifications, interface, controls, networking, data handling, lighting/rendering, user guidance, etc.
Describe how the game will be distributed/delivered, and how any patches, upgrades, or revisions will be handled.
Legal issues
There must be clear documentation regarding the handling of all trademarks, copyrights, licensing, contracts, etc. for the assets created for or used in the game, including third party code, engines, and tools to be used in the game creation.