Fallen

Nathaniel Wilson has earned two Medals of Liberty and a Crimson Heart in battle but has lost his father in the Third World War. The Red Fist alliance was crumbling and their capitals taken or besieged as Nathan is back home dealing with raising his brother and PTSD after being drafted as a young adult. That is, until the A-bombs dropped.

(Fallout inspired but is a hybrid between Fallout, Rage, and ,when power armor is in the mix, Doom.)