Okay, No Lunch is for free, and I don’t know if there is a catch.
But what I do know is that you can order a Sudoku CD for Free at Think All dot com. According to ThinkAll “The game is fully customizable, so you can select the colors and design exactly how you like it – once or every time you play. At any time during a game, get hints, check your progress or simply solve the game”.
As well as Windows as Mac OSX operating system is supported. The CD comes with 10 other fun, challenging puzzle games. Happy Puzzling!