The Asian F2P version of Counter-Strike was just released for the western world on Steam, includes the original CS and coop/PvP zombie game modes. : r/Games
Steam Community :: :: Counter-Strike Nexon: Zombies
Have You Played... Counter-Strike Nexon: Zombies? | Rock Paper Shotgun
Nexon
Counter-Strike Nexon: Zombies (2014) promotional art - MobyGames