Easy "Silent Assassin" rank on "Curtains Down"
-A scope for your Silverballer is required. When the level begins, run up the steps and to the right. Throw a bomb and immediately pick the lock on the first door on the left. Walk in and explode the bomb, then wait a moment before sniping the man up in his private box and the actor walking on stage. Put your gun away and get out of there. If done correctly, you will get a "Silent Assassin" rank in under a minute.
-Note: Only the W2000 sniper rifle is required. When the mission begins, go in the door to the right of the coat room and wait for the worker to go in and sedate him. Take his clothes and hide him in the container, then get out of the bathroom and go down the set of stairs. Find the person painting the door leading to the basement, then go downstairs and into the basement hallway area. Find the stairs leading up to the actor's rooms and get to the next set of stairs leading up, but not the metal stairs behind the double doors. Once you are in the small hallway, travel all the way down and into the office room. Take the keycard on the desk to the light room, then go downstairs and find a way back into the basement. Go back to the staircase you used to first walk down to the basement, then go up. Go up the spiral stairs until you are on the top floor, then go into the light control room and unpack your sniper rifle. If you are fast enough, you will have arrived there with enough time to make the shot at the execution part. If not, wait until it happens again. You must shoot D'alvade in the head just when the executioner fires the blank. Blood spray will confirm the hit. Wait there until Delehunt appears on the stage and kill him, then drop or pack up your rifle and get out of there. You should have a "Silent Assassin" rank.