Interesting game, let down a bit by the controls. Having right click to select first and second pieces for joints was not intuitive, nor was q for motor in an otherwise mouse only game.
Resetting the entire level and deleting what you have done was also a little annoying. It meant I was not inspired to build complex machines, but instead I just put a block past the finish line with a spring attached and let bob fling themselves over. Decent potential, just needs polish.