Games GDD

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From what I read, the Game Design Document is Pretty much a detailed Scope doccument or "bible" that can change as you go throughout the designing process. It describes  and details everything such as  gameplay all about each level, character dialogue, etc.  It will give your the rundown of all info on the character, what they will look like, wear do, their storage, pretty much all details about what you want in the game .

It serves as a communication tool for developers working in a big team for big games and is good at getting all your ideas and anecdotes across so if you are not working on the game one day and another developer is, your notes and design will help assist the other developer with information you planned so they can continue to work on it.

"Designers use design documents to record their design decisions as they are made. This way, you do not have to solve the same design problem multiple times." this segment  states that it is also a very good memory aid. You are only human after all and can only retain so much information, you are bound to forget some of your ideas or designs. A good way to make sure this doesnt happen is to create the Game Design Document and input all and every detailed little brain wave that comes to mind so you wont forget it later. You may not use it all but it will be there for future references and may even use it for future games. 

No Game Design Document is the same so you can create yours anyway you want. What works best for you and your work flow will determin what your doccumentation will look like.

Some good rules to go by for a decent Game Design Document would be:

1. Know your target  - It is important to know what group this doccument will be aimed toward and must be user friendly to avoide confusion and miss communication.
   
2. Keep it short  - KISS (keep it simple stupid) is one of my favourite acronyms and is important when it comes to this doccument. It is just better for you to maintain and read. It can become dull and boring if it is dragged out and longwinded.
   
3. Use clear terminology - You want to ensure that you use terms consistently, and possibly create a glossary for words that seem unclear. This means that if you start writing some slang words or more difficult terms others may find hard to understand. make a note, indext or "glossary" so it is more easily broken down for others to read and understand

These are three of many rules you should research in order to make a quality Game Design Doccument. 

Gameplay pillars are the next staple that needs adressing. This is where you will work on the core features of the game in which challenge the players. for example if you are building a shooter game the shooting mechanics need to work flawlessly and as realistic as possible. For flying games these will be the controls and how you fly the plane, the physics of the game etc. It is your job to make sure these pillars are up to standard and you cant have a game without its core features. Assassins Creed, for example, has core pillars which allow the player to (1) Fight (2) Navigate and (3) Socially Stealth within the crowd as mentioned in the Acagamic article here.