I purchased this for my son knowing full well that i would be assembling this. He was so excited, however the set is flimsy, and the chain lifter and cranks do not work as advertised. The chain lifter as it moves around and picks up a marble, gets stuck because of a poor design flaw. The area where the two pieces that attach on the right side and allow the marble to sit inside the buckets causes an issue when using the crank. As these two pieces come together there is a seam that is created and the buckets from the chain lifter get stuck in the seam prohibiting further movement of the chain. Any sort of struggle to pass the seam has the marbles falling out. Another issue is, if you bypass the seam, the marbles fall out before they land on the first track. The cranks are flimsy and require perfect balance and positioning of your hand to make all the gears work correctly. This is the 2nd set we have purchased and by far the worst. The sidewinder is a little better, but still has the crank issue.