: A comprehensive redesign of the original campaign featuring tougher encounters and entirely new routes.
: A secret military research facility filled with traps, puzzles, and custom lore. It includes creative mechanics like using gas cans to unlock paths. 100 addon maps for left4dead2 l4d2 left 4 updated
These maps are often cited by the community for their exceptional polish, often rivaling or exceeding official Valve campaigns. : A comprehensive redesign of the original campaign