I remember seeing this one come out a week ago or so and from screenshots and from app store description still hadn't a clue what to do other than your supposed to deciper a code or word. Maybe I thought you unscramble a word like in Muddled, Million Dollar Password or TextTwist Turbo but it's not like that at all. Finally Enigma Machine lite version comes out and there are instructions within and I love it. Instant purchase for me at $2 for full version of Enigma Machine. Now you might think this is a clone of the classic Mastermind (Masterbrain is my favorite version on iphone) game but with letters. Well not exactly since in Mastermind you can go through the process of elimination by putting say all blues to eliminate that color. In Enigma Machine every guess requires a valid word. If your trying to guess what 5 letter word it is then you MUST guess a 5 letter word each time. On the ticker it shows how many letters are correct (nothing to do with positioning like in Mastermind) just saying those letters are contained within the word your trying to decode. Then on the paper thing tap it for fullscreen history of your words. Tap once to mark red and tap again to mark green. On the right side it'll show the # of correct guesses of letters if any within that word. This is useful for identifying correct letters. Then on the typewriter keys you can mark green /red letters your absolutely sure of. Anyway I watched Valkyrie tonight and was pumped I guess with the WWII Hilter theme so maybe I got over excited a bit. Quick note for those trying the lite version and think it's easy you are correct 3 letter words are super easy. 4 letter word will give you much more of a challenge. Five letter words are even more so. So the lite version is just showing you how it plays. Developer has a nice video on his site showing gameplay which I can't remember if it was there on launch day or not.