Named Game of the Year by over 50 publications, Valve's debut title blends action and adventure with award-winning technology to create a frighteningly realistic world where players must think to survive. Also includes an exciting multiplayer mode that allows you to play against friends and enemies around the world.
There is the black Mesa mod/project which revamps the graphics if that’s a showstopper for you. But it’s worth playing.
it’s nothing like a mod they built a replica from the ground up