Tunnels.bsp
Created by Sir Cobalt

You probably know how to load this map but just in case:

1. Extract the bsp file to your maps folder in your half life root folder,
most often located in C:/Program Files (x86)/Steam/steamapps/common/Half-Life/valve/maps. It does differ based on where you
installed Steam.
2. Launch Half-Life. As soon as you get to the main menu, open the console (I trust you know how) and type "map tunnels" without
quotations, obviously.
3. Play the map. It will boot you back to the main menu when you finish it.