Is the Mac version no longer available now? The game card only says Windows and it doesn't show up under "Mac games"

Seriously not cool. Did you download it when you first got it?

No, unfortunately. I had this dumb idea I could trust GOG to store my purchases online. I guess I was wrong.

I'm loving the newly "fixed up" forums. It seems I could not "reply" to your post. It errors every time. I hope you see my reply somehow...

This was unexpected, and I actually didn't realize this until the start of the Digital Game Factory sale.

I'm guessing that this was a casualty of rights issues, and is a good example of why Mac support took so long to get to GOG, and why it'll be a while before we'll see Linux support for at least their more classic titles. The game was originally published by Eidos (who I assume owned the original IP). Then they got bought by Square Enix (according to wiki it's S-E Europe). According to the GOG came card however, Imperial Glory is apparently owned by Digital Game Factory.

I can only guess that S-E/S-E Europe lost the rights to distribute Imperial Glory, or the rights reverted to Digital Game Factory (they're British, so perhaps some former Eidos staff are there). When that happened, the rights to distribute the Mac version probably weren't covered; either the rights to the Mac port went back to Feral (which still sells it), or GOG's right to sell it were lost in limbo.

Again, this is all my best guess; I don't have any insider information, but it's what I believe to be the likeliest one, given what I've observed about the legal issues in bringing games to GOG. All isn't lost; you can still play the Windows version in Wineskin and it works perfectly, at least, under my testing under Snow Leopard. The only issue I had was that I had to dial down the graphics options significantly to keep performance up, but that's more due to the limitations of my hardware (64 MB GMA 950) more than anything.

If I'm going to play a Windows version of something, I might as well play Total War.

I just realised this now as I was going through my back catalog of GOG games to download. I was a bit behind but this is a lesson never trust an online vendor, download as soon as you buy. I know some older games that had Mac versions years back the Mac versions were sold by other distributors and made mac friendly with them so perhaps someone else out there owned the rights for mac. Still would be nice if GOG notified owners that this had happened, or leave a note the downloads section for the game to advise.