What's in a Design Document??
Chris Taylor wrote pretty nice template:
It's also recomended by GameDev.net.
SROAK: Design Document: Table of Contents
I would write more about the game mechanics and gameplay and less about
specific elements of lets say animated objects. And in general go from general to specfic. Always say more than you can but don't make things up. For example it is good to limit design choices to accomandate for programmers (and other producing trades) to start work.
Hope it helps
So it's more just of notes as you go along in the development? Ok, I just really wnated to know for some reason, didn't wanna ask my Lead Game Designer, I don't need people thinking I am working for some one else Lol.
It depends on your approach.
Most companies ask for a TDD early on in development, before a lot of the work starts so they can know the riskier items.
My company currently gets "Mini-TDD", or what we call "Mini-Tech Plans" that outline the risk involved with particular tasks, so we can keep the schedule current.