For most of the reactions in the game: You can already define custom material reactions; you can even add script to reactions.

For wind, you would probably need a density/velocity map.

Awesome :O
I made a perpetuum mobile with fast-spinning-right-click-clockwise :D

Funny game!

I found an exploit, look: An infinite laser beam!

Great idea, but I think, that implementing this would make changing material engine necessarily, as it supports only solid, sand and liquid materials.

Also I have an idea to fix problem with single pixels. Median filter. When digging/changing terrain other way pixels that are changed, and those around them should get medianed, so there wont be single-pixel lines left.

But yes, material simulation like in Powder Game would be nice, but very CPU-intense. If you could find a way to optimize calculations it would be good idea to implement it.