Still have that unplayed since last years summer sale. I liked the demo, and it seems well regarded, but most people also seem to give the impression of the game being somewhat of a chore.
I have played for about 8 hours so far, and only yesterday did I finish a puzzle and think "I can't be arsed to do one more tonight". The puzzles are fun and there is a real sense of accomplishment when you come across one that perplexes you, but I definitely can see how some may find it repetitive or boring after a while.