The Battery Clatter music is short, but very exciting as you wonder which battery will come out. Sadly, it's not on the OST.
The main theme, doubling as regular trainer battle music.
Nick D.'s theme is sad and a little frightening, and a very well-crafted piece of music.
The Lover's Cliff music sounds wistful, sad, and happy all at once.
The Present Day World Map and the Past World Map are both very good; the present-day theme has more GBA instrumentation, while the Past theme goes retro.
The time travel theme is heard in only a few scenes, but you hear it often enough that it leaves an impression.
The Legend Battle music is intense from the get-go, and really makes you feel like you're fighting a Legend.
The final boss music drives home that this could be a hopeless fight, but you keep trying anyway.
The credits show thanks for saving the world and a job well done.