What are some alternatives?
When comparing Metro Exodus and Xonotic, you can also consider the following products
Duke Nukem Forever - Duke Nukem Forever is an Action-Adventure, First-person Shooter, Single and Multiplayer video game developed by 3D Realms and published by 2K Games.
Quake - Quake is a series of first-person shooter video games released by id Software.
Team Fortress 2 - Team Fortress 2 (TF2) is the sequel to the game that put class-based, multiplayer team warfare on...
Unreal Tournament - Unreal is a series of first-person shooter video games developed by Epic Games.
Warface - Warface - is a free online shooter with diverse PVP modes, exciting PVE missions, outstanding arsenal and millions of fans around the world!
Counter-Strike - Counter-Strike is a PC-exclusive FPS video game developed by Valve Corporation.