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.
A Sven Coop edited map pack for Blue Shift campaign. After several years, I finally finished my own take on the coop experience of Blue Shift, I called it 'Serious Shift: 3.05 Project'.
Might be worth making clear that this is for Sven Co-Op rather than the original Half-Life.
I did post it in sven coop section
It's also popped up in the 'Addons' section for Half-Life, which is where I saw it. Guess it's just ModDB being weird.