This is SniperLand by -N- Team.   Awesome map... and completely different from the maps being released lately.  Lots of fun with this one right down to the working cranes and some wicked ass air cannons that blast you far as hell.  This map is great.  Comes with two versions Day and Night. Read the readme file included for 16 players in Coop play.

Play Modes Supported:
Team Survival
Survival
Team Hostage
16 Co-Ops
Co-Op Hostage
Co-Op Mission
Co-Op Terrorist hunt
Single Player Lone Wolf
Single Player Story Mode
Single Player Hostage Rescue
Single Player Practice Mode
Single Player Terrorist Hunt

5.5mb file.