In a game called Red Faction, you could blow parts of certain cave walls, sometimes revealing secret areas and sometimes revealing nothing but un-blowable stone.
It could be nice if we could cut through certain areas of cave walls (by either digging or blasting), atleast up to a certain degree, and they\'ll slowly regenerate.
It could be nice for diggers, as they\'ll have to actually dig through stone to find valuables, instead of simply going to an object that generates the valuable constantly and collect from it.
It could also be just a fun thing - blasting through stone walls just because. And perhaps sometimes lead to secret passageways.
To make sure no one will dig a hole through the stalagtite, there will be undestructable stone to make sure it\'s possible only to dig to a certain point.