If you go to the youtube page instead of watching it here, you can change the resolution to 480P.
If you watch about 1:00 to 1:15, and compare the height of the core columns to the height of the building to the right, you can see they clearly disappear at the last look.
For most the debate about whether it was or not a demolition has been over for years. Only the ignorant, low IQs, or stoodges say it wasn't a controlled demolition. Agpoop and Buckfart are all three though, ignorant, stupid, and stoodges.