Dark Cloud 2 is a much better game than the original.
Actual gameplay remains fairly similar, characters don't level up, but the weapons gain experience and evolve into new weapons depending on the path you choose.
As before, there are some different characters to control, and this time you can even bring along supporting characters who will repair weapons or make bombs for your use.
The graphics are quite nice (cell-shaded) and the voice acting is all pretty good. The story is a little odd at times, but it will definately keep you coming back for more.
Fishing is back again (although I definately don't have the patience for it), as well as a golf-like mini game.
Definately the neatest addition to this game is the ability to take pictures of objects in the game and use them to create inventions. Once you have an idea you simply need to collect the required materials and you can actually produce your invention. Most inventions can be quite useful in your adventures.
This game is much better than the first one - definately give it a try!