[Aardappel]

A voxel is about 2 inches / 5cm in size.

Yes there is a single world grid, so all world objects are axis aligned and same size.

On top of that it can have floating "sprites" which are used for monsters, particles and such.

[Aeolun]

Having just played it, you seem to have worked around the destruction problem by removing voxels one chunk at a time. But I’m still baffled by the sheer number on screen at the same time :)