Very Easy way to win: Delay the deliveries as far as possible. If you have to send 300 chests, buy 295 and wait until a few seconds before you loose to buy the last 5. This way, you've got more money (and maybe time, i'm not sure) to trade opium.
This way, I've won on the first try with little effort and 9000 silver to spare.
I like it, but if would be nice if the map would show how many exits a cave has after you discovered it, and not after you used the exits.
That way, I could see the paths I missed/skipped and I wouldn't have to search one single missed path for more than an hour
A funktion sending all soldiers into/out of a bunker with one click would be realy nice. It totally sucks having to send all of your soldiers around every twenty seconds.