i tested it with few people from the [[3374,hashtags]] channel from irc.freenode.net
we used latest hamachi + haguichi for linux (to emulate LAN over internet)
we tried everything. connecting directly with ip(hamachi one) at the end of the game executable and looking just for if the game shows on the LAN list , but wasnt able to get connected at all. there seems to be no log about it also.
and yeah. gamespy doesnt work at all as well. looking at the nethog (to monitor my connection resources) i can see that the game even doesnt seem to try to connect. at least no bandwidth is used.
hope go see this resolved asap, since this game is not really meant to be played alone.
ofc better option would be steam linux support, with integrated steam servers.