The guys over at Croteam
have updated their site with some very interesting information about the Linux port of Serious Sam 2:
Linux port of Serious Editor 2 and Serious Sam 2 client is nearing its end. What is left to do is some internal polishing and a few minor issues to resolve.
As we are currently preoccupied with implementing new features to the Serious Engine 3, the linux port will be finished and shipped as soon as we catch some breath.
We've posted a few screenshots of the game and editor running on Linux up in our screenshot gallery