When you have to get the boat downstream, kill off the two Sintrek, the Grenadak, and the other monster. Do not worry if one of your characters dies; just take out the monsters. When this is done, destroy the two stones in the river, then the bridge (completely obliterate it), then do the same for the water mill. Then, destroy the dock. Do not be in the boat when you do this. After the dock is destroyed, jump into the boat, release the controller, and an intermission sequence will start.