Just type in the letter, and try to guess the word (there are only 3 & 4 letter words thus far but I have like 200 words and I'll add more later If you guess the same letter twice it will count the second one wrong regardless of whether or not there was one of those letters in the word because I have given you all a list of the letters you've guessed and so you should try to guess new letters.
I drew the thumbnail in Ibis paint, the rest was done in scratch bitmap. I used the pen feature because clones react to messages, but stamps do not :)