I just played through the demo for about 3 hours. It's a fun game, worth recommending, but it's not "stay up until 4am, soiling myself" fun like it could have been.
I think the main problem is that it centers all around ONE type of puzzle and only offers a variant of that puzzle when you try to capture a monster. Also, that one puzzle involves a lot of luck to be good. Especially, since you are alternating turns with the computer .. it takes out alot of the strategies of setting up your board for cascades. There is no sense of accomplishment when you hit a 5 combo .. it's almost 100% luck.
After playing Puzzle Pirates, it left me wishing this game was more like that game. Duels with opponents have seperate play boards. Each "task" has a different type of puzzle. Definitely adds variety to the game.
I will still buy the PC version when it comes out. Maybe once I get more spells/weapons/etc it will add some depth to the one puzzle game.