I'm certainly no marine architect, but my big concern is the modular approach he used, sticking hull modules together one by one. Apparently only using epoxy to fasten them together.

IMO, this seems like each seam between modules would be a weak point (all along the seam) and would be where the up and down flex forces on the hull would concentrate. I think they are where leaks would start and propagate (along the seam) and possibly experience a catastrophic failure. If there was a full length keel tying the whole boat together, this might help, but I did not see one in the video.