This demo uses an engine similar to wtf-atabimp, with a few new features, such as high speed OpenGL rendered voxels and a clean up of the mp3 playing code. All voxel operations (such as "adding" and "carving out" voxels) are done in constant time, with the "housekeeping" of the voxel render list occuring at render time.
This demo is built on a framework that allows the entire demo to be driven by lua. The lua files are included, and can be modified freely. There is also a console available from the demo itself, providing a "live coding" environment which permits complete modification of the demo while it is running. There is an unmarked pane splitter at the bottom of the window which can be moved to reveal the console. The console now maintains a persistent session, so the command history is maintained between runs.
Thanks to cTrix for his wizardry in creating this awesome music for the demo!