Dark Cloud is a great RPG that combines old and new game features and makes them work together almost flawlessly.
The most interesting part of this game is the Altamillia system. Your adventure doesn't stop after you've cleared the dungeon. You have an entire town to rebuild before you're allowed to advance to the next part of the game. Along with rebuilding the town, you also need to build based on residents' requests. Although it may be sometimes tedious, the extra effort does not go unrewarded.
Dark Cloud seemed like more of a test game rather than a full new experience. Everything seemed thrown together and got really repetitive after a while. The only time you experience anything new is when you take on bosses or get close to finishing the game.
To sum the game up, its a hack-n-slash with some extra features. Nevertheless, it is a great game and is worth a play-through for any RPG fanatics.
I highly recommend playing through Dark Cloud if you plan on playing Dark Cloud 2. You're experience playing the sequel will be enhanced as you notice both the similarities and differences from each game.