Difficulty : High
How rogue-like is it? : Quite ... the view is not as far back as most rogue-likes are ... you are pretty much right up to the character you control. The battles aren't real-time, really ... they are that super-quick turn-based, where you only have an instant to react.
[Side-note : I finished Chocobo's Dungeon of Forgotten Time, recently, on the Wii, and it is an amazing rogue-like ... with some lovely new features, like job classes, and a mirror that allows you to replay dungeons, over and over ... it is not that hard though, compared to other rogue-likes.]
Additional note : the controls for this game are slightly better on the PS2 version.