Halo and Half-Life combine in wild new mod, bringing two of my favorite games together in one — here's how to play, and how it works

A screenshot of a Spartan model in Halo: GoldSource.

Aside from titles like DOOM or Quake, I think you'd be hard-pressed to argue that there are first-person shooters more influential than Valve's 1998 hit Half-Life and Bungie's critically acclaimed 2001 Xbox flagship Halo: Combat Evolved.

The former revolutionized FPS (first-person shooter) storytelling and introduced the GoldSrc engine — a modified version of Quake's that was the foundation for the Source engine used in popular games like Left 4 Dead, Team Fortress 2, and Titanfall.