It's a Quake 1 map (So don't put it into the Half-Life folder :) )
How to run:
1. Put ldj7_base.lit and ldj7_base.bsp into [Quake directory]-id1-maps folder
2. Run QuakeSpasm.exe or other quake 1 engine
3. Press [~] or [Esc] - Option-Go To Console to open the console
4. Input 'MAP LDJ7_BASE' then press [Enter] to open the map