If you want similar,S.T.A.L.K.E.R. is pretty similar to it. It is inspired by it as opposed to based off so if you want an actual Roadside Picnic game,it probabaly doesn't exist. Would be intesting though.
Edit:Woops. Entirely misread the post. As for a story,I have had some ideas about a Roadside Picnic like story. Just like the games though,it is more inspired,by it than an actual Roadside Picnic story.
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