First of all, this game reminds me HIGHLY of OOT (There's Gerudo desert, Kakariko Village, and more).
Also, there are lots of dungeons, but 9 main dungeons.
Temple of Time
City in the Sky
Palace of Twilight
Also, the Twilight King is a man named Zant who was tricked by Gannon to release him.
The final boss has 5 phases (3 different bosses, 5 stages).
First you fight Zelda, who's been possesed and you fight her like Phantom Ganon of past games, just more difficult. Then you face the beast, Ganon, who's a boar, you fight him in two phases. Then you fight Ganondorf, you first fight him on Horse back, then you fight him with the Light Sword and face him when he weilds the Sword of Darkness (they look like Lightsabers...)