Nih has just released The Turret Fortress -- a highly unique map which he's been working on for more than a year.

Players must fend off 12 waves of monsters by constructing sentry turrets and a few "special" friendly units. The players save up for these sentries and special units by killing the attacking monsters and surviving waves. If too many monsters make it to the end of the map, the players lose.

Just to make life even harder for the players, random "Panic Events" will occur throughout the map. Such panic events could involve hostile soldiers infiltrating the base and installing a virus in the Turret AI, or the generators powering the sentries breaking down.
Download now!   (Mirror)

By the way, remember to check out Sniper's Radiation-related post if you missed it before.   ...Also, You Only Live Once.