I'm requesting to upload the .ogz-file =P.
So far seen on the screenshots; I wouldn't add grass outside, but rather somewhat scorched earth (to make it feel more fitting to the theme, unless you're trying to make it more like a secret facility which hasn't been discovered yet but I doubt that as there's an old building on top of it).
I know lava is a tempting material to add as it's dangerous and a quick and easy light source; but does it really fit the theme? Perhaps it could be retextured by some pure red texture, so it's more of a dangerous glowing liquid.
materialreset
texture lava "<mad:1/0/0>misanthropx/white.jpg"
texture 1 "<mad:1/0/0>misanthropx/white.jpg"
P.S.
Not sure if that piece of config is correct as I'm not on a pc right now.