SMOD is a single player mod of Valve's first-person shooter Half-Life 2. The new content consists of many new NPCs and weapons, new gamemodes, comprehensive customization and tweaking options, new abilities for the player, and new features to the gameplay, such as level randomization and simple branching in the otherwise linear flow of the main episodes.
The main purpose of this modification is to make UnderHell on Source SDK 2013 C++ source code. All gameplay, that has been shown in the video is in work in progress stage and is the subject to be changed.