This is probably the easiest level of the whole game. It takes hardly any time beat it and usually when someone first buys the game, they can beat it the first time they play it. Since it's so easy to beat, you probably don't need a strategy guide, but since I have one for all the other levels, I decided to add one for Dam.
Tips:
1.) It's good to use the zoom lense in this level to easily pick of soldiers quietly.
2.) Make sure to kill all the guards near the red alarms so they don't set the alarms off. Otherwise you'll have a swarm of soldiers on you in seconds.
3.) Collect all the new ammo you see. It's worth it.
Walkthrough:
At first, you start out in a small corner. Peek around the corner just slightly and pick off the soldier will your silenced PP7. Walk to the spot where the guard was (the one you just shot) and wait. At the tower in front of you, there should be a guard coming down the stairs. Use your crosshairs to pick him off as soon as he comes down. Walk to the tower (where the 2nd soldier was), peek left, and drill the guy sitting there like an idiot. Walk up the tower and pick up the sniper rifle. Note: the sniper rifle uses the same bullets as the KF7 Soviet, which the enemy soldiers are using, so make sure to pick up all the stray guns. Once you have the sniper rifle, walk to the side of the tower facing the dark tunnel. Zoom in (press R and use the top C button to zoom in the fullest length) and snipe the guy on the left in the head. Once you shoot him there will be a guard on the across from him who will start running toward you. Try to hit him in the head, if you can't, wait 'till he comes up the stairs and get him with the PP7.