It is a binary file, but it also has a very simple format. It just contains the width, height, and reference number of each texture, followed by the texture data, which is a bitmap. See the source code for help reading this file, or devise your own file format. Both the game.ini and the game.tmf files were created using Fred, which is a primitive level editor I wrote. You are welcome to use and modify Fred if you like.
Most game developers prefer to write their own customized world builder tools.
Fred is provided as an example of how to use Fastgraph to write such a tool. Fred is not really a product itself. That is, we don't sell it or support it, and I will only work on it if I feel like it. It is an interesting program, though. If you want to have a look at it, you can download it here .