RE: [DS] 6mm Bugs

G'day,

>For my DS alien rules I had the following for Crawl
>Easy=Roads
>Normal=Open,Light Scrub
>Poor=Rough,Cultivated,Urban,Hills
>Difficult=Mountains,Light Woods, Rivers/Streams (crossing)
>Impassable=Swamp,Dense Woods, Open Water.

Why so tough on them at the upper ends? Was it a balance decision? Based
on
things that "crawl", "squirm" or "slide" currently I probably would've
said:

Easy = Roads, Open
Normal = Light Scrub, Cultivated, Urban, Hills
Poor = Rough, Light Woods, Rivers/Streams (crossing)
Difficult = Mountains, Swamp, Dense Woods 
Impassable = Open Water.

Though even then I can't see any trully impassable terrain and would
probably put Open water in the difficult - the ultimate swimming tank ;)

As for speed, they could be fast or slow... depends on if you need to
balance out the range of terrain they can clear etc, or how much you're
willing to pay for the privilege. 

Cheers