the people who made the film were artists not critical thinkers and definitely hard right
one of the things that totally sticks out in my mind as wrong with the wtc part was the pools of liquid metal, they said jet fuel couldn't burn hot enough to melt it. surely the energy stored in the building being released within a few seconds would have resulted in such heat. also you have convection, burning in an enclosed space would have slowed the rate of heat dissipation and with sucking in oxygen from lower levels would have turned the building core into a furnace. those people werent jumping because they thought they had a chance for survival, they jumped because they didn't want to catch on fire and burn to death.
as for the white powder, concrete dust. get yourself a 10 pound sledge and a couple concrete blocks, smash em to bits and try not to get the same kind of dust.