What does it mean to be the "spiritual successor" to The Walking Dead? Well, for starters, it's means you have big shoes to fill. Secondly, it means that you're filling a post-apocalyptic void that was recently vacated by one of comics' biggest success stories.
GUNG-HO takes place in the near future, when the "White Plague" has almost completely decimated humanity, and civilization is only a sweet memory. The world as a whole has become a danger zone, where survival is only possible within towns or fortified villages.