GameGuru is a “WYSIWYG” engine. That stands for “what you see is what you get.” It's very straightforward and allows very rapid prototyping of levels and even whole games with a minimum of fuss. Models are plentiful and cheap, common code components are included with it, and level design is very intuitive. So why then am I about to talk about making a technical design document (or TDD)? What's the point of using a “WYSIWYG” engine if you have to do planning? The answer is that more complex engines require more complex planning and with an engine as easy to use as GameGuru, such documentation could be seen as counterproductive, right?