Concerning the multi-player - they may be trying to get the release out there while working on this feature (which used gamespy or the other service originally and was removed). It's quite possible, depending on the access GOG has to the source, that it will be added at a later date. They've done this to other games as well. I don't know if they wait to gauge the success of the game or if they plan on adding features from the beginning, if they do. Then again, it's possible it won't ever be added back in (in a manner that doesn't use the original MP service) just like you see the early Age of Empire and Dungeon Siege games on steam (single-player only). This is a great game, even in single-player.
