Named Game of the Year by over 50 publications, Valve's début 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.
15 maps from a Hungarian author, made in 2002. Thanks to PlanetPhillip for finding this map set.
The mapping here is quite basic, but the scripting and gameplay are good enough. Nice finding!