>>23561
Don't see why you couldn't make it from the ground up, if you use an engine like UE4 or Unity it would be even easier.
The voxel system itself isn't too hard, especially if you want the simplistic one used in the original (you could also improve upon it, or add over it a marching cubes algorithm, though in that case you'd lose the blocky look). The game itself is simple as fuck, I don't think you'd need more than a week to code the game mechanics and content once you got the voxels down. The netcode could be a bit of an issue if you are inexperienced but nothing that can't be fixed with some effort.
TL:DR relatively not hard at all if you got the drive to actually do it.