Game won't init steam on 10.6

[Romulator]

If the Mac Steam version has since been updated, there may be a Amnesia_NoSteam application you can run in the game's root, else it is likely an issue with Steam as Mudbill has said. As a Windows user, when it does occur for me, I end up resetting Steam's background service or by closing and reopening Steam by going offline and online again. What appears to be happening is that Amnesia is checking to see if Steam is running, and cancelling it from running if it seems Steam is not running.

Beyond what has already been suggested, if it is possible to reinstall Steam in case some dependancies have become corrupt or missing, that would be my next step. From there, I can't really offer much more help because I don't believe it to be an issue with Amnesia itself.