Several improvements have been prepared for the Steam version.
Recently, Zombie Panic! was released on Steam for PC. The original modification for Half-Life was introduced back in 2004.
This is a cooperative survival horror project about the confrontation between humans and zombies. A group of survivors must complete several tasks or destroy all the infected. If a player dies, they will be reborn as a living dead and begin hunting former allies.
The Steam version supports modern Half-Life's 25th anniversary, achievements, the "Workshop" and contains a number of technical and graphical improvements.
The Zombie Panic! page on Steam is available at the following link.