One of the most welcome improvements was the fact that in the "central dungeon", in this game a tower, which is returned to several times during the game, previously completed portions of the tower do not have to be repeated. Many of the items in the game are variations on standard Zelda items: bombs, bow, boomerang, whip. There was also an item which let you blow gusts of wind (using the microphone) and a wand which let you do some really neat puzzle with sand. The wand would hard the sand and make it stand up as a raised platform, allowing link to create barriers or elevator himself.
Princess Zelda plays a more crucial role in this game since her spirit became disembodied. She follows you throughout the game, but not in an annoying way. As a spirit, she can possess certain armored enemies called Phantoms. The Phantoms only occur in the central dungeon and come in a few varieties. The co-op'esque gameplay provided by this mechanic allows for wonderful and interesting interactions with your items.
The boss battles were all wonderful, the ones at the end were especially great.
This game does feature extensive train travel as a core of the game in a way that is somewhat similar to Wind Waker and Phantom Hourglass, though in a more rigid way. There are some special gates that facilitate travel via teleportation, so overall, it's on par with the travel in the other two.
Overall, it was a wonderful game.
