·         You will need to have OpenAL installed on your machine to run games developed with GTCS1Lib (required by MonoGame, for audio support, "AL" stands for Audio Library).

 

·         The best I can derive, OpenAL consists of two runtime libraries: OpenAL32.dll, and wrap_oal.dll.

 

·         You can find OpenAL installer from here: https://www.openal.org/downloads/