Wow, this episode was really quite the rollercoaster. The top builds were quite good from an engineering perspective although the tiniest of negatives: they did lack a little bit in the art department.
The show itself was probably the best so far as it seemed like things were tightened up just right in editing.
Also, I'm not sure how natural the ending was but if it really did happen dynamically like that then respect and hugs go to them. If it was some kind of stunt then until the end of time may all your bricks either fit too tightly or too loosely!