I just spent two hours hammering away at a handful of thorny puzzles in this game. I broke out a graphical editor (Monodraw, you're awesome) to prototype ideas. I took many, many photos with my phone. I drew intricate diagrams in a paper notebook. And after each puzzle was successfully checked, I was far less motivated by the audio "ding" than I was by the satisfaction of making the right connections and drawing the correct inferences from all possible sources of available information.

Mr. Blow often talks about "unethical" player motivation in game design, and rightfully draws some skepticism when he does so. But he has absolutely delivered one compelling alternative in The Witness.