Hey everyone!
We just released a small hotfix to resolve an issue where several users joining a Lobby through Steam may cause the lobby to stop functioning properly.
Oh yeah, in case you didn't know, you can now right-click someone's name on your Steam friends' list and "Join Game" if they're in a lobby, or "Invite to Game" if you're in a lobby and want them in. :)
As always, if you're experiencing any issue, please don't hesitate to contact me personally on Steam, or open a ticket at http://support.castlestory.net
Thank you and have fun. :D