Voxelstein 3D is an indie game based on the original Wolfenstein. The game uses Ken Silverman’s VOXLAP game engine to render voxels in software. The levels in the game are fully destructible – and by fully we mean fully.
The game world is built from tiny cubes called voxels – similar to the way that Minecraft is made, but much smaller. There are over 37 million in the first level. Rendering a world like this is slow (especially without hardware acceleration), but there is an advantage: voxels can be added, removed or otherwise altered very very quickly. This enables all kinds of cool stuff, including fully destructible worlds!
Download it from voxelstein3d.sourceforge.net