I'm thoroughly impressed by this particular sound in the keyboard...usually wind and brass settings are pretty awful on keyboards in general, but kudos to Yamaha for a warm, listenable timbre.
Semi-improvised...the ostinato bassline was precomposed, as was one of the main themes. It kind of reminds me of something out of a Final Fantasy game. I feel like I'm stepping onto an airship to go battle Sephiroth and save the world.