Atomic Heart is an action-adventure first-person shooter developed by the Russian studio Mundfish. Set in an alternate Soviet Union, the game immerses players in a world where rapid technological advancements have granted the Soviets extraordinary powers. The protagonist, known by the codename P-3, is dispatched to a secluded facility that has mysteriously fallen silent. Combining action-RPG and survival-horror elements, the game offers players multiple strategies for confronting various enemies. Initial reactions to Atomic Heart have been largely favorable.