We all know Garry's Mod, the landmark physics sandbox mod for Valve's Source Engine that can be used for everything from creating custom game modes to messing around with Half-Life 2 characters ...

Garry's Mod has entered the Guiness World Records: Gamer's Edition 2025 as the best-selling PC exclusive of all-time.

In our world, though, Garry's Mod won out, and JBMod is only just making its way to Steam now, 18 years later. "JBMod was the first mod ever released for Half-Life 2," developer Team JBMod explains.