Was sceptical... But it's a good game of mechanical foresight and thinking ahead. Gears are (randomly?) chosen for you, shown through circle sizes on the top right "bullseye", and you place them where you think they need to go. This kind of game would really shine with an editor, community level sharing, and different game types.
Hard It's a nice game. Challenging but the difficulty ramps up far too quickly for a casual gamer. Better for people with some time to invest and enjoy very challenging puzzles.
Fun, easy at first then. .. Solid & tight UI/controls, nice learning curve.
Good, but needs less random. Either of these changes would make it a much better game: a. Let the player pick which size gear to place, or b. Have the same sequence of gears every time.
Not very intuitive Needs User Experience improvement.