Why are the Autumn Moon games Windows only?

This came to mind after seeing how so many adventure games are Windows only and that Wintermute can only create 2.5d adventure games by enabling DirectX 9.

Is it possible to make an adventure game like A Vampyre Story in Panda while keeping it compatible with both Windows and Mac systems?

Yes, it is: Panda supports the cited platforms and offers the needed features.

Thank you, flavio.

-edit-
I would of said this earlier, but it landed in my spam folder for some reason.