Once the shader pack is placed in your shaderpacks folder alongside a compatible shader loader like Iris or OptiFine, you can turn its retro horror atmosphere on or off directly from the pause menu.
Activating the Shader Pack
1. Load into a world or stay on the main title screen, then open Options and select Video Settings.
2. Click on Shaders (or Shader Packs, depending on your shader loader).
3. Select Oldhorrorvibes Shaders from the list and click Done or Apply.
4. Return to your world. You will immediately notice bright colors stripped away in favor of a washed-out retro palette and cold, tight lighting.
Switching Back to Vanilla Lighting
Because the pack makes dark spaces intentionally uncomfortable and unsettling, you may occasionally want standard visibility while sorting storage or building complex redstone.
1. Pause the game and return to Options > Video Settings > Shaders.
2. Select Off (or disable shaders via your loader's toggle button) and apply the change.
3. If your shader loader includes a quick-toggle keybind in Options > Controls > Key Binds, bind it to an accessible key so you can flip between the eerie atmosphere and normal lighting without opening menus.