Jisatsutou, I Am a Hero Recommendations
Characters in both of these titles are subjected to a dramatic shift in their environment that pushes them towards an almost primitive existence. Survival is key in both of these titles.
Being able to survive in both stories is a key theme
Essentially, both series are about survival. The horror elements are explicit and shows how the characters are in mortal danger throughout their story. Both series also focuses on character growth as they develop relationships along the way. There is a decent amount of graphic violence to illustrate the reality of the grim circumstances. Both series' story also unravel startling revelations. In general, both series are a treat for any survival horror fiction fans.
Both feature MC's with mental issues in a survival situation.