Sorry about that. My guess is Apple update invalidated a bunch of old software security certificates, and I no longer have the ability to update GCK.
Someday I'd like to completely remake the old IG titles, but it'll have to wait at least until our latest title, The Zone: Stalker Stories, is done. And even if I do, they likely won't have Mac support because Apple makes it so prohibitively difficult for indie devs.