I'm working on adding a lot of optional quests for the new levels, they will be given by Sakharov. You can directly go to Dead City from Yantar, the gate is in front of X16 entrance.
A unique quest is given by Sakharov: "Bring the Enchanted Tear". A very long quest, where you have to fight for the stolen recipe, and do numerous transmutations to become able to transmutate the Enchanted Tear, which holds unbelievable power. All of the ingredient artifacts will be merged into a Cobblestone so good luck to have a ruined transmutation as well!:)
The artifact which Strelok shows to Doc in one of the cutscenes, it supposed to be the new megamodificate artifact in OL. Look at my comment below. You can only equip one, this is to avoid becoming overpowered.
Artifact activation, a new artifact transmutation, a unique quest and 43 side-quests for the new levels! Read the included readme docx and guide pdf files before playing!