J'ai trouvé ça sur un obscure forum:
Perso je trouve qye sZone est beaucoup plus english-speaker friendly que STALKER Online...In the beginning there was S.T.A.L.K.E.R., by GSC Game World. Then came STALKER Online, for legal reasons a "completely unrelated" game made by different developers. After legal issues they renamed their game to sZone Online. Then, most of the developers of sZone split off and began maintaining their own superior version called Stalker Online. This general is for that game.