I decided that after all the snow I’d been having in game, there should be some snow on the ground, so I did my first ever JSON hack to turn the dirt and grass tiles white and give them properly wintery names. (Modding 0 (1%))
It got me to thinking whether this sort of thing could be handled automatically, and whether more might be done, like having water turn itself into Ice, bushes turn into Snow-Covered Bushes can’t be lit on fire (you could still Smash them to turn them into Undergrowth which could then be lit), and so on.
And then THAT got me thinking about whether the terrain could have various effects that would interact with different kinds of footwear. Regular snow could be the same as dirt and grass, while Deep Snow could impose a movement penalty unless you have snow-shoes or cross-country skis, which would let you move fast but would make it hard to fight in melee, ice could give you a movement bonus and melee penalty if you wore skates, neutral movement and neutral melee if you wore cleats or ice treads on your boots, and a penalty to both movement and melee if you wore normal shoes…
Just some ideas.
Oh
Oh wait, wait!

There could be snowmen in the construction menu, requires two heavy sticks and must be built on Deep Snow.
And snowballs to throw at zombies!
