Yes, here it is at last the first game in the Penumbra Series.
Read through the TODO file for various known things that should be cleaned up / fixed.
Included are project files for Xcode, Visual Studio 2003 and Cmake (for Linux)
We encourage everyone to contribute code to this project, so just sign up for a github account, create a fork and hack away at the codebase. We will start an Open Source forum on the Frictional Games forums as a place to talk about changes and to submit patches from your forks.
All code is under the GPL Version 3 license. Read the COPYING file for terms of use of the license.