Penumbra from GOG on Linux?

[Rudism]

I bought the Penumbra Collection on GOG.com a while ago, but never got around to actually playing them when I still had a Windows machine. Now all I have is a laptop that runs Linux, but I see that GOG doesn't have the Linux version of Penumbra available for some reason.

I would obviously prefer to play the native Linux version over installing and setting up Wine for emulation. I can extract the game files from the Windows version using innoextract--is there anywhere I can get just the Linux binary/executable and dependent libraries to get it running natively under Linux? Or is there some way I can get the native Linux installer(s) that doesn't involve re-purchasing games that I already paid for?

Thanks