Sounds incredible and awful at the same time. I just took apart and put back together an upright piano and it was so labor intensive. I can imagine this being a total headache with a relative high at the end once it's done.
The amount of dedication and skill it takes to build something like this is massive. I find it amazing how people keep up the motivation to contribute to such projects for hundreds or thousands of hours. I wish I could keep up with something even half as long, I find that these days I get so distracted and easily frustrated that I stop working on my cool ideas after only a few days. I have to wonder what keeps them going to be honest.