My son got this for his 5th birthday and we all like to play.  We take turns setting it up and figuring it out.  I thought it might be too hard for him at first, but if you start at the very easiest level, even the young kids can figure them out.  The 5 year old hasn't gotten too far into the various puzzles, so he is still working on the easy ones, but he just glows each time he solves one!  Such a good feeling!  I sat alone with the game after the kids went to bed and worked my way halfway through the deck--kinda addictive, but lots of fun if you like challenging the way your mind works.