This isn’t post-apocalyptic fiction, its Civilization II!
Lycerius has played his game off and on for the last decade taking his save all the way into the year 3991 A.D., into a horrific swamp of a world. Nuclear wars ravage the earth and as a result the human population has dropped by nearly 90% since its peak 2000 years ago (startlingly close to home). The polar ice caps have melted 20 times due to all of the nuclear war and what little land that is left is pretty much unusable due to nuclear fallout.
A nonstop war between the player and 2 other AI characters has raged on for 1700 years. The way is between the Celts (Lycerius), the Vikings and the Americans. Ceasefires don’t last more than a turn or two and pretty much are just a giant facade.
Lycerius says that his goal over the next couple of years is the end the perpetual war and finally use engineers to clean up the remaining swampland and make it habitable again (right now any engineer that strays outside is almost immediately nuked).
The post on reddit has spread like wildfire and has even spawned its own sub-reddit dedicated to ending the war in the game, aptly named “/r/theeternalwar“. Good luck, Lycerius, Earth’s future is in your hands!