The Earth has been ravaged by viral pathogens, the death of billions observed by the orbital colonies and deep-space habitats that were largely unaffected by the Outbreak. Terrified of infection, nobody came to help. Less than 30 percent survived the first few weeks. Then came the 2nd Wave of infection, spreading steadily outwards from the impact points, and that was when the horror really began..
Yellow Dawn is a Cthulhu-mythos based RPG in a post-apocalyptic world.
Yellow dawn uses adapted mechanics of Call of Cthulhu and offers a very comprehensive ruleset (which is probably best used with some discretion). The game world has the flexibility to allow the DM and players to work in a wide variety of game tropes- 'zombie escape', 'medieval explorer' or 'space adventurer' within the same World. The excitement really comes from the CoC-style global conspiracy underpinning the World, creating the paranoia that allows long-story arcs to develop. My favourite individual scenarios are generally the zombie escape type as the peril induced by these is very compelling