This map concept would work really well.
I'd offer a few suggestions. First, strike any vehicles from the map. Make it infantry-only. I love the idea of small groups of soldiers sneaking around a pitch-black forest.
Second, include custom sound settings for the map (include modified default sounds or con files for existing sounds) so that footsteps can be heard from farther away. Also, try to code sounds triggered by player actions, such as large underbrush making a rustling noise when a player passes through it.
Also, I'd actually give the map the slightest amount of light, but only within a small radius around the player so he can see brush and trails. Use map fog to make everything far away pretty much black.
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