Just some ideas from my old hard drive 
Your second image reminds me of the troll fortress in Boulder's Gate [2?]. At closer look they are very different, but both have a 2.5D- mountains and both have a sandy flour. *nostalgia*.
This is the second image btw: [img]https://www.omnimaga.org/art/mockups-'please-say-this-is-going-to-be-a-game'/?action=dlattach;attach=18500;image[img]
(Note I presume that is sand in your image and I presume the different levels are "steps" in a mountain's side.
