Run. Think. Shoot. Live. Source. BMS Classic is a game-wide modification of Black Mesa that aims to revert some of the changes made in the 1.0 and 1.5 updates, as well as fix various bugs and oversights, improve performance, and reimplement missing setpieces and sequences from the original Half-Life - removing self-locking doors, allowing the player to backtrack and explore at their own leisure, restoring puzzles, rebalancing combat and supplies, and more.
The lights in the "back halls" of WGH (on your way back down from the surface) have been edited, making the area darker and moodier.