Now the early-access package is now available on AOZ page. The price is $4.99 while the launch price will be $8-$9.99.
https://koexstudio.itch.io/all-of-zhem
2 maps are completed but there may be some hidden bugs here and there. Then for the Building map, I still need more time to figure out the events for it, for example where will the zombies appear next and how interesting can I make it.
I am considering adding in a 4th map based in China. Let's see..