Xash3D is a powerful, open-source game engine designed to be a highly compatible, cross-platform replacement for the proprietary GoldSrc engine (the engine used by Half-Life and its expansions). It allows you to play GoldSrc games on modern operating systems (Windows, Linux, macOS, Android) without the need for Steam or legacy patches.
git clone https://github.com/FWGS/xash3d
cd xash3d
mkdir build && cd build
cmake .. -DXASH3D_GEARBOX=ON
make
Solution: Opposing Force uses CD audio tracks. Xash3D needs MP3s. You must rip the CD audio tracks from the original disc or find a community MP3 pack for "HL Gearbox." Place them in gearbox/media. half-life opposing force xash3d download
Half-Life: Opposing Force - A Classic Game Reborn with Xash3D Report: Playing Half-Life: Opposing Force on Xash3D 1