Such games are very helpful in developing your cognitive abilities..they stimulate your thought process and put your mind to test..
Storm, well I dont think they are not winnable, but as you said, you've to plan each and evry one of your moves beforehand..
RB, I would suggest not to use any hints because if you do so, it wouldnt help improve your observation skills..secondly, even if you do use hints, they only show you the possible moves, the strategy you've to formulate on your own, which cards to get rid of or otherwise..
Naweed, thats quite impressive, do you find the Fortress layout any harder?
PuNk, thats great man! :d which layout did you play on?