More Puzzle goodness, less of other stuff.
You know what Puzzle Quest 2 has? Puzzles: lots and lots of puzzles. If you like/love match-3-gems style gameplay, then this is right up your alley. The main combat puzzles are still loads of fun, as are most of the additional mini-game puzzles. The unlocking puzzles can be frustrating as you try and line up specific gems, to specific points on the board, with limited turns. Stick to bashing open every lock and door; especially if you want the Achievement.
if you came to this sequel expecting the surprisingly full RPG experience of its predecessor, you will probably be disappointed. The story is threadbare, and completely unmemorable as it shoves you down a generic dungeon. there is almost none of the warmth, humor, or depth of the original's story, and the feature set is just as pared down. There are no more mounts to capture and train, no items to forge, and what seems like a much smaller set of secondary spells to learn, many of which are mana color-swap clones of other spells.
By them end of the game, unless you have mastered any of the few really high damage attacks, and have the ability to make those hits count, the battles can get really drag-out tedium. Thankfully, the Ai is not nrealy as much of a cheatin' bastard as it was in the previous games, but it will keep you on your toes with 4-of-a-kinds and the like.
So if you liked Puzzle Quest because you like gem matching puzzle games, then hell yeah go buy this now. If you liked it because it was a fun RPG to roll around, soa up characters and story, and kill stuff in...try the demo first.