Most important is the time that you need for the final task. Notes, time bonuses and "cryptologic bombs" help to solve the tasks. For non-expertsthere are also two easier levels.
"During the game everyone can find out what methods were used to beat Enigma as well as try to break messages encoded with the famous machine cipher. Enigma, a cipher machine considered unbreakable, was defeated by three brilliant mathematicians. Now, together with other adventurers from around the world, you have a chance to become an Enigma codebreaker."
Team with three people can join worldwide. Registration under www.codebreakers.eu