Yeah, that one was tough, And finding the machine behind the drawing make me feel unfair too. Maybe other puzzles do have the same problem at some level, but they are fun or make me get the humor some way. I think make it easier and more interesting would be the point.
BTW, I think it can have fans on steam as free game, or even with a price(maybe around 1$). The game provided me a pretty interesting 30-min experience at least, some will love to pay for that I think^_^