well yeh i was gona say that it looks a bit light for being underground, as in reality i would also use ramps instead of steps and i would put water but... i dont think u can make water murkey in nightfire...
looks very interesting though, one idea could be to make more than 1 flag and spread them out a bit
map does look awesome though, uve done a great job dude, keep it up and i hope it ends up lookin as much like reality as possible, i would advise an ambient_generic with some eerie music set to play everywhere just to show players what kind of map they're dealing with

Pop goes the sniper! :-)
BOOOOM! goes the pistol! :-D
Why does network cable have 8 wires?
To electricute an octopus...