The first Half-Life was a nexus point for what we consider the modern FPS. Valve's shooter presented a fully realized world, and a compelling narrative to go with it. Gordon Freeman's tram ride to Black Mesa sets the tone, while the walls of the secretive research facility tell their own stories. Then Halo comes along, which ups the ante with gigantic sandbox levels and an entire universe to decipher. We wouldn't have the shooters we do today without Half-Life and Halo. But what would happen if we smashed both games together? Now you can find out. Continue reading New Half-Life mod rebuilds Halo multiplayer inside Valve's original engine MORE FROM PCGAMESN: Whatever happened to Half-Life 3?, Best old games, Best FPS games