The best free alternative to Counter-Strike is Unreal Tournament, which is both free and Open Source. It is designed completely from the ground up for the new style introduced in Big Sur. Hi, I have a PC game called Counter Strike 1.of 2 - Why OpenGL Updates Take Forever and Why Vulkan Might be Coming After All - posted in Mac OS Related: So the following is the result of an exchange between myself and a redditor by the name of lgroeni.The Goal of Kisak-Strike is 100% open source CS:GO from the 2017-era for perservation, enthusiast use, and long term maintenance. ' CS: GO is being developed by Valve in cooperation with Seattle-based Hidden Path Entertainment. Counter-Strike: Global Offensive on Mac.