[kcdusk]

I'd keep interactions with the players brief, to a minimum. Dont overdo the descriptions etc, let the players imagine their own dark and moody environment, sometimes its what they dont know that agitates them. If the players want to know more, make them think, and ask specifically. FtF or play by post, interaction, interaction, interaction.

Aside from that, use some music or sound effects, or pictures (worth a thousand words).

copeab's on the right wavelength. Give the players nothing to start with (or very little). Make them work their way up from nothing, hard work for small achievements = player pride, engagement and satisfaction.