this is real sucks, man. sorry for your lost. I dont think there is actually a way to get your back unless Mt Gox or btc-e agrees to cover your fund (most unlikely)
travain is more popular with way more players around the world than tribe war. players will to buy loads gold to train, build and NPC. (i was a pro player)
and its a german based game company. i heard bitcoin is very popular there
if it is offline, they you dont have to worry about hacker, you might get virus on your USB (what the chance ) or you could put on a voucher, paper wallet....