Review on Mechanical Boyfriend - ROBOTIME Laser Cut Locomotive by Lance Harrison

Wow that was a great build, I think it would be difficult for a child. I did most of the assembly and my son helped put the pieces together. Several pieces were difficult to put together, not at all as easy as their video, which must have had perfectly smooth pieces. There were several burrs and splinters on the pieces popping out of the board. They provide a skinny 1 inch square of sandpaper. Three pieces broke during assembly, but only 1 came with a spare so I had to apply superglue. Luckily, these parts were aesthetic and not movement related. After we were done, the gears moved smoothly. But turning the spring did not move. I've tried to figure out why and troubleshoot, but nothing worked, and I can move the gears manually. I even watched a 30 minute assembly video and everything seems fine, I just don't quite move as advertised Disappointing after 3 hours of construction.