S.T.A.L.K.E.R.: Shadow of Chernobyl
The game uses a software feature called the "X-Ray engine". It features an alternate reality theme, where the second nuclear disaster happens at the Chernobyl Nuclear Power Plant in the near future and makes strange changes happen to the area around it, which create a lot of mutated animals, plants, and change the laws of Physics. The game has a storyline that lets the player have a lot of freedom, and features gameplay features such as trading and two-way communication with NPCs. The game includes features of role-playing and economic games.