Apparently Jumble Key is a crossword solving game, and in part it is. But really it is an educational tool to help you when you get stuck because you can`t find the word you need to solve a crossword.
Jumble Key lets you generate words from the patterns you indicate; just insert a term and it will give you all the possible words you can build, according to this pattern, from the different combinations of letters.
Apart from being a fun game, Jumble Key helps you enrich your vocabulary, at the same time as solving crosswords and puzzles where you have to find the missing letter.