Phantom Hourglass is a game thats great, but suprisingly unthought out in some areas.
The game features some pretty easy dungeons for the most part, with semi challenging boss fights. THen there's my biggest complaint about the game; the temple of the Ocean king. Its straight up annoying. Its basically a stealth aspect b/c you go threw stages with enemies you cant beat and its timed on top of that! To make matters worse you have to go back after beating other dungeons, making it worse. It just seems to me that they didnt really play through that part of the game...i say that because on one trip to the temple you compleete your standard zelda puzzle but those damn phantom enemies get in the way and make it next to impossible.
If you want a fun game with major drawbacks get this game. It doesnt suck at all, just has bad gameplay elements. Also the sailing parts are pretty fun, and the game takes full of advantage of DS's features.