How to make a good puzzle game

I love puzzle games. But it’s not beating them that’s the exciting part: it’s understanding them. Whether mulling over a cryptic crossword or somersaulting through Portal’s portals, there’s a moment of epiphany which, for me, pretty much transcends all other moments in gaming. But how do you design a puzzle to best provoke that eureka moment? What gives a puzzle its aesthetic, its pace and texture? Why does one puzzle feel thrilling while another feels like a flat mental grind?

http://www.rockpapershotgun.com