◇ ‘What is “Muv-Luv Unlimited: The Day After”?’
A spin-off title of the Muv-Luv series, continuing from “Muv-Luv” and “Muv-Luv Alternative”.
The second title in a spin-off series derived from “Muv-Luv Unlimited”, which branches into a different future from the anime-adapted “Muv-Luv Alternative.”
After protagonist Shirogane Takeru sees the heroine escape Earth in “Muv-Luv Unlimited”, this story portrays the people left behind on Earth who nonetheless keep battling against their fate of extinction.

◇ Story
The massive gravitational anomaly caused by Operation Babylon turned Earth into a world of death.
In Tacoma, part of the U.S.-administered Seattle Imperial Lease Territory—one of the last habitable regions for humanity—stood Imperial Japanese Army Lieutenant Tatsunami Hibiki.
Day after day, he fought to defend Seattle against the relentless BETA assaults.
With food supplies dwindling and ammunition nearly exhausted, Hibiki continued his desperate fight to stay alive.

More details on the official game page of Muv-Luv Unlimited: THE DAY AFTER - Episode 01 REMASTERED ...