What are some alternatives?
When comparing Call of Duty and Quake, you can also consider the following products
Battlefield - The latest news and updates for all things Battlefield, the EA and DICE video game franchise.
Xonotic - Xonotic is a free (GPL), fast-paced first-person shooter that works on Windows, OS X and Linux.
Doom - Doom is a science fiction horror-themed first-person shooter video game in which players assume the...
Counter-Strike - Counter-Strike is a PC-exclusive FPS video game developed by Valve Corporation.
Overwatch - Stylized team-based FPS
Unreal Tournament - Unreal is a series of first-person shooter video games developed by Epic Games.