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.
This mod is very good. It's a lot like Brutal Doom but for Half Life 2. My only problem is the Ravenholm chapters. The feeling of being alone is ruined completely and the fact that the HECU marines from Half Life 1 are there literally ******* breaks the game's lore into a million tiny pieces.