If you want to see the things in the feature vote list added to the game, then learn how to program in C, grab Visual C++ 2008 (the express edition will be enough), download the source code from the downloads page, grab the Direct X SDK (I think you want the 2009 version), then get coding. There's other things you need to get in order to compile the game though. ViciouZ knows.
2008 and 2010 express editions work, so maybe get one of those installed as well and try using that. Also, post the errors. You will probably need to install the DirectX SDK and libpng/zlib to get paintball to compile, also either install libvorbis/libvorbisfile or disable the ENABLE_OGG define.
I personally don't recommend any version of Visual Studio newer than 2008 unless you like dealing with the "%linkeroutput doesn't match the $(targetpath)" errors. I think T3RRORI5T is planning on upgrading the Visual Studio solution/project files to Visual C++ 2012.
I tried compiling the source code, but I get an error that says something like "PthreadVC.dll is missing". Maybe you won't get or maybe you will.