At minute 52:38 and minute 52:46 respectively, the drawbridge capstan is show being turned, with no rope on it, either connected or unconnected to the drawbridge being lowered.
Then, the ropes shown lowering the drawbridge obviously have no weight or tension on them as evidenced by the slack in the byte connected to the drawbridge and the manner in which the ropes are shown swaying slightly.
At minute 1:19:15 a piece of stonework which would weigh several hundred to a thousand pounds falls from the top of the building and bounces off one the fleeing citizens.
At minute 41:03, the canoes are clearly shown traveling downstream, at minute 41:42, the canoes are forced to portage up a cliff and now travel upstream on the same river.