Valve Hammer Editor is described as 'More informally known as Hammer, and previously Worldcraft, is Valve's in-house level editor for GoldSrc games. Version 3.4 is included on Half-Life SDK, and version 3.5 is the last version to be designed for GoldSrc' and is an app in the development category. There are 2 alternatives to Valve Hammer Editor for Windows, Linux and Mac. The best Valve Hammer Editor alternative is TrenchBroom, which is both free and Open Source.
TrenchBroom is a free (GPLv3+), cross platform level editor for Quake-engine based games. It supports Quake, Quake 2, and Hexen 2 and runs on Windows (10 and newer), Mac OS X (10.14 and newer) and Linux.
