A new Half-Life mod adds raytracing to Valve's venerable first-person shooter, a shiny slap of 2023 lighting technology in a 1998 game. I normally think such anachronistic upgrades look awful but this one works for me. Rather than just slam fancy modern tech into an old game, the mod wants to change the whole look. And it succeeds in a surprising way: by making the rest of Half-Life look older.