Alright.. sorry for another update, but i made a mistake previous one.
After many hours of boring tests i`ve figured out that snow landscape layer is based on how many other objects pre-placed on map. And game counts only OilDrums and Mines (which is available to control from WA scheme editor).
As more objects we have on map, as less layer`s number we should have for snow.
That also explains why we had different results with Kaos scheme and my weap scheme. Kaos scheme has 0 mines and crates, my scheme had 8 (now 20) mines and crates.
Playing with this values and 3 different schemes i`ve made a formula that allows to make good layer number for snow, to be shown behind the landscape.
tested it on small and large maps, from 0 to 100 objects. All works just as it should.
So here is an Update.
Also.. i`ve made an ice-effect (
http://px.worms2d.info/forum/viewtopic.php?f=13&t=559)(losing viscosity + increasing speed if slippering is angled) as separate lib, which is small increasing from 0 to 90% every turn. It affects to all of the objects on map. Enjoy!