I just want to say that, even a year later, this mod has been very nice.  It adds just enough challenge without being rediculous.

Melfice

This is offering a halfway point between the two settings present in the game. Default setting is that sand/gravel falls straight down if there isn't a block under it, dirt floats. The other vanilla option is that dirt ALSO falls, but that ALL falling blocks have "sideways instability" which means they can slide off sideways (eg: when making a pillar/wall). The mod simply makes it so that sand/gravel have the sideways feature, but dirt doesn't. It removes the crazy behavior you get if you use the sideways instability vanilla option, where animals/drifters will cause massive landslides all the time whenever moving around on hills because the dirt keeps sliding.

So, what exactly does this do?
From what I'm reading, it basically means soil is stable unless it's being disturbed by the player?

Or am I oversimplifying it with that?