-To easily complete certain missions, massacre all the Nazis. To do this, go to a semi-hidden place where the Nazis must to make a right or left turn before they can see you. You must be in range to shoot them with a pistol before they can see you. For example, in the "The Asphalt Jungle" mission, a recommended place to do this is behind the wooden fence near where the zoo keeper turns to go back inside the zoo. When you are in place, fire a warning shot. Nearby Nazis will hear it and run towards your location. They will fall in line while running to you. Start gunning them down when they come into sight. You will see them first and kill them before they see you (three shots per soldier). Note: This cannot be done in missions that require stealth.
-When trying to kill a tough soldier, stand up momentarily. When he is looking at you with the light green line of sight, go back down and hide. The Nazi soldier will approach to investigate without raising the alarm. You can now kill him easily.