Coop Box is a gamemode for Garry's Mod.
Coop Box is using Andrewtheis' HL2 Campaign gamemode. This gamemode allows you to play in Half - Life 2, Half - Life 2 Episode One and Half - Life 2 Episode Two Campaign and allows you too to play Custom maps made by users and developers.
Custom maps progressing -
Tunnel of Doom - Kill 100 Zombies and get to the end of the tunnel.
Westside - Going through old town and going up to the rooftop. Kill combines and zombies until you escape the old town .
Dev Fort - Kill upcoming combines with your friendly Rebels to survive.
NO SCREENSHOT YET