https://store.steampowered.com/app/1465460/Infection_Free_Zone/

Face the first few days after the survivors come to the surface. Gather resources, scavenge the buildings and create a Zone that will be able to stop horde attacks at night. Conquer Prologue to prove you're ready for the upcoming full version of Infection Free Zone.

“The Mad Virus” has spread throughout the world with the speed of jet planes. The infected are highly aggressive, fast and strong.
In a couple of weeks, society collapsed. Cities are empty. There is no electricity, no water, and no food. Yet, there are a few survivors...Establish a new “Infection Free Zone” wherever you choose. Set up shelters and production facilities. Adapt existing buildings to new needs. Build new farms and cookhouses. Establish defenses with walls, gates, and towers.Utilize your knowledge of the city. What is the best place to defend? Where were the grocery stores, where were the pharmacies? Where would you look for weapons?
Remember that it’s dangerous to search the old buildings, there might be some infected lurking in the dark!Each night your settlement might be attacked by large hordes of the infected. Fight them off with every tool available - melee and ranged weapons, vehicles, walls and towers. Strengthen your Zone and create an impregnable fortress, or simply enjoy rebuilding entire cities!Your Zone is not the only one that exists. Your survivors will surely find other surviving groups. Some will be friendly and willing to trade, but others will be extremely hostile. There might be some fighting involved!