I'm not sure I really understand the idea. As for how hard it is to mod the game, it depends partly on what you're doing. The way things are done with the DLLs, you can pretty much do anything by writing an appropriate new DLL. Of course we don't know anything really about how the shell DLL works, so user interface changes wouldn't be easy. Also, changing behavior but keeping it localized to one level, or a set of levels is somewhat limited right now. We can write new tech trees, and give them a name other than the default. Then levels written to use the tech tree by that name can be moded by editing that tech tree. Unfortunatly, that's the only type of sheets file that is easily exchanged. The other ones seems to be loaded by the shell and don't depend on the level DLL.