Thanks everyone!, I never actually left this completely, but I always had months where a thousand other things came in the way
As for challenge, I intend to have some kind of permanent death if so chosen, with some inheritance system where you'll get or adopt children/pupils to be your successor when you eventually die or grow old, where skills and belongings could be transfered in some matter, be that via training or something else.
Different worlds will be different in every sense I hope, all will be underground cave environments, as I'm a big arx-fatalis/underworld fan, ranging from lava caves, mushroom, frozen, to wasteland and jungles, if an object looks different it is different.
It's all written in c++ and I'm using sdl and opengl, so it should easily port to mac and linux when I get to that point.
I'm currently working on building the entire system the game runs on, which means everything but gameplay as I'm still figuring that out, I'm looking toward something that drives you and gives you some purpose.
One would be going out to find recipes that adds to your crafting-list, the other would be gaining some kind of experience or skills to further give you abilities to make things.
Another would be finding friendly npc's that you build houses for and they'll pay you back in gold or services such as building, fetching food for you or guarding the town.
playable alpha is still a bit away ;P
And as for scale, it can currently be scaled to any size, and run at any resolution, so doing crazy stuff like this is possible:
http://www.eldpack.com/files/eldgame_world.png