Fearon was sent a copy of Half-Life by Valve prior to its official release, and while playing it, he toyed with the game's code, figuring out how to spawn enemy creatures in multiplayer maps. Fearon's work had initially been done before Valve released the software development kit for Half-Life, requiring him to craft the modification atop the existing Half-Life distribution and to work with multiplayer over slower internet connections, such as phone-line modems.
Fearon was given an early copy of Half-Life by Valve prior to its official release, and while playing it, he experimented with the game's code, figuring out how to spawn enemy creatures in multiplayer maps. Initially, Fearon's work had been done before Valve released the software development kit for Half-Life, necessitating him to create his modification on top of the existing Half-Life distribution and collaborate with multiplayer over slower internet connections.