I am a big fan of Puzzle Quest: Challenge of the Warlords. So much that I ended up buying it twice, once for PC, once for my PSP. So I was looking forward to the sequel, Puzzle Quest: Galactrix. But unfortunately that sequel turned out to be much less good than the original. :(
The main problem of the sequel is that the hexagonal puzzle that is at the base of all combat and other mini-games is a lot less fun than the regular one. It is much harder to plan series of moves, and that is not just because you have to think in which direction the stones fall, but also because the ways are shorter, and often the previously invisible stones that fall in from the border have a bigger influence than your planned move. Thus the puzzle becomes more luck-based, and that can get really annoying in some of the harder challenges. And as "hacking" the gates to get elsewhere is often one of those harder challenges, this gets annoying quickly.
While many elements of the sequel are similar to the original, Infinite Interactive did remove some fun elements. For example there are no character classes any more, which limits replayability. And while the original had tons of spells, items, and other various bonuses, these appear to be much rarer in the sequel.
So if you are interested anyway, I seriously recommend you first play the Puzzle Quest Galactrix demo before spending any money on this game. To me it appears as if the developers tried to quickly cash in on the success of their first game, instead of building a more lasting legacy. Sad, really.