After seeing the movie, I can imagine the writer of the movie was once standing at the bottom of sands hotel looking at how the rooftop looked like a boat and thought of himself "hmm, maybe I can destroy this building for the climax and have the rooftop fall to the river and float like a boat" but anyways, I loved the story and how kitou kid is also present but they killed physics WAAAYYY TOO MUCH. (fkng roof of the hotel wasn't even pushed but it hovered conveniently to the river) and the super saiyan powerup thing is too much for an exaggeration.