In need of a game to play with a friend when they come over? Perhaps Serious Sam's Bogus Detour [Steam] is what you want as they just added full split-screen support.
In the recent patch they finished off the split-screen support, which was previously added in, but in an experimental unfinished form you had to run commands to access. Now it's finished enough to be included by default.
On top of that, they've also fixed several crashes (hopefully some of the issues I experienced!), improved support for High DPI and other general improvements. You can see the full changelog here.
In an earlier patch, they also fixed Steam Controller (and other gamepads) support on Linux. I tested it just now and it does indeed work a lot better!
About the game
Serious Sam’s Bogus Detour is an all-new action-adventure in the legendary Serious Sam saga from Hammerwatch developer Crackshell. Battle through beautiful Mediterranean locales, dangerous biological weapons labs and even high-tech moon bases as a one-man wrecking crew or in four-player online cooperative for maximum chaos! Dominate the chaotic Survival and Versus modes or make your own mods, modes, and even total conversions with the include game editor. Serious Sam’s Bogus Detour is the biggest little Serious Sam game ever made!