Half-Life Mod - Hazardous Course 2

Although it's a mod for a first person shooter, the player can only wield a weapon at the designated target range. So it plays more like an adventure. The difficulty is quite challenging, but the rewards are accordingly. The Basic Training is peppered with hidden Secrets, which reveal tools, shortcuts, control rooms, and other features, to ease almost all challenges. There are two Secret Levels and one Bonus Level to discover, and to complete to access the final part of the Hazardous-Course.