Pretty cool idea by using open street maps you can download the location you want and play the game there, defend your neighborhood or loot your house.
The reviews seem decent but mention it needs a lot of tweaking as it just released on early access, like water not affecting where zombies can walk or elevation not being a thing.
Maybe this can get some more people interested in mapping
I wonder if they pull the data straight from Overpass or if they use a cached copy on their servers.