Half-Life : Echoes is a single player mod for Half-Life developed by MrGnang and was released on August 10, 2018. It is set in the Half-Life universe, taking place during the Black Mesa Incident. The player takes control of a scientist simply known as "Subject 12" and his perspective of the Black Mesa Incident. It ties into plot threads brought up in the later Half-Life games such as Half-Life 2: Episode Two, such as The G-Man being responsible for delivering the Xen crystal sample and starting the incident