Simply awsome
There are the dungeons to explore, with multiple levels and various 'medals' to win by doing special feats on each level. You're given incentive to go back and replay them to achieve all of the special requirements.
There are your weapons, which you can customize in various ways, build up into better levels and combine together. There are towns that have vanished that you have to rebuild, adding in an animal crossing/sim feel that lets you wander around the town you have built and admire your achievements.
There are so many built in subgames that the game can literally keep you occupied for months. There is fishing. Sure, you say, you can fish in several other games. But in this fishing world, you can sell your fish. You can eat them. You can put them in your aquarium! Each fish is different. Now you can watch them interact with other fish, or even breed them!
There's picture taking while you explore your world. But the snapshots aren't just used for decoration. There are multiple characters to work together, each with his or her own special strengths. There is time travel.
Highly recommended for any adventure-RPG loving game player!
It has excellent voice overs and on the calibur of Legend of Zelda OoT.