Pathologic

In Pathologic, you'll follow three outsiders who arrive in a contaminated town. Each party member--a highly educated bachelor, a farsighted Ripper, and an eccentric girl--must survive the horror and play a vital role in the fate of the doomed town. The town constantly changes and reacts to your behavior and random circumstances. To battle the omnipresent enemies, you must develop a variety of individual survival and resource-hunting strategies. The game's three heroes act independently--when you play as one character, the two rejected heroes plot against you.
summary by MetaCritic