Russian game studio Mundfish.
Russian game studio Mundfish released its first work, Heart of the Atom, which won wide acclaim with its unique Soviet aesthetic design and solid game quality. Atom is produced by Mundfish, which is headquartered in Cyprus, Europe, and Heart of Atom is also the first game of the studio.
But most of the employees in the studio belong to Russia, so Heart of the Atom is a game developed in Russia.
Official website's introduction to Heart of the Atom shows that the game inspiration of Heart of the Atom comes from bioshock.