Really enjoyed it so far and have found it engaging and fun EDIT Ive been playing this for a while now and this is one of the best mobile games I have played. The stories are great, the puzzles are the right amount of challenging and it truely is free. You can definitely get through these without purchasing anything In saying that, i have happily purchased a few key packs. Just to get through a little quicker and throw the dev some $ for their great game! But you can watch ads for free keys!