For the last week I've been experimenting with biomes, ala Minecraft. Basically, I was successful in creating some randomly placed forests using a simplex noise generator. Perlin noise is widely used, so there isn't a ton of support out there for simplex. However, simplex is faster comes out with nicer looking results. Since I'm a freak for optimizing code, I couldn't let myself use Perlin. The results are pretty cool. The next step will be to tweak the borders of these regions and make sure that they blend into each other. Right now, there are hard lines between regions. Blurring these lines has been a bit tricky, but I can handle it.
The only real problem that I have with biomes is that players may go out to explore these areas rather than follow the linear path that would take them further up the wall and through the game's story. I wouldn't want someone wander off to some random volcano in the distance thinking that they can get a boost there, when really the nearest elevator is a kilometer in the other direction. It's a linear game set in an open world, so there is a real possibility that players could get hopelessly lost.
My solution may be to have a system that clearly defines waypoints for the player. Mirror's Edge had a button that would turn the player to face the next waypoint in the sequence. The challenge would be to teach the player to use this function. I've designed the game to be mostly intuitive, using WASD + mouse controls. Adding another button to the mix is unintuitive, which means an on-screen prompt/tutorial would be required. I have been resisting adding unnecessary complexity to the game, but this may be unavoidable.
An alternative would be to have some clear and consistent visual signal that would indicate where the next waypoint is. A light, a flag, etc. would serve this purpose. Will have to experiment a bit with both systems and see which one works best.
Oh, and Against the Wall was featured on Giant Bomb the other week!