Here are download links for the Windows, Mac and Linux binaries. Meaning the .exe, .app and .bin files for all the Penumbra games. You can use these to play on any platform regardless of where you bought the original game and for what platform.

For example if you bought the Windows DVD you can use these files to play on a Mac or Linux system instead.

Windows:
http://thedarkswarm.com/downloads/penumb...in_win.zip
http://thedarkswarm.com/downloads/penumb...a_dlls.zip - Add these to redist folder if you are using Linux/Mac version to run in Windows.

Mac OS X:
http://thedarkswarm.com/downloads/penumb...in_mac.zip

Linux:
http://thedarkswarm.com/downloads/penumb...in_lin.zip


HOW TO:
The easiest method:
-Install the game for your original platform
-Copy the game folder to the other computer
-Unzip the penumbra_col_bin_*.zip and place the new .bin/.app/.exe in the same location as the current .bin/.app/.exe from the old platform.

You can also extract files from the installer files, there are various options on how to do this. If anyone is interested in writing platform specific "how to"s for this method send me a pm with it and I'll update the post.