I had an account without cs:s and it had all textures, but i couldn't see weapons or zombies. Sometimes i also get black with purple on my normal account [with cs:s and all games that can be mounted in gmod], but only on a few props.
it lies alot of times, because it's free to edit. sometimes people put garbage in it, but it's thrustworthy for most of the articles. if we are getting to old artists i would say: iron maiden - aces high
the missing textures aren't caused by not having cs:s, only the errors are. I once had the same problem and reinstalled gmod. so if cs:s shouldn't work than try this instead.
finally someone that has the red bug too, it happens if you are last human for longer than around 60 seconds and die, but don't become zombie as you normally would. it also happens with normal zombie hitting you [but mostly chems]
I playtested it with roborobb and a few others and it has a bit low fps outside. i have 30 fps with my hd3870 for me that isn't that bad, but for people with low hardware it is. inside is normal. [around 70] the map itself is high quality and it reminded me of an area in stalker. good job