Sure, the title is highly subjective. To me, as someone who really enjoy's hack and slashing, this is the best game on PSP right now. It's perfect for me - I have about 30 minutes on the train every morning and evening, and the bite-sized missions, etc. are just the thing for some diverting play. It's quite amazing to be holding something that looks pretty much like a handheld PS2 - the graphics, sound, and gameplay seem very close to PS2 quality.
If you love roguelike games, and you've managed to fork over the loot you need to get a PSP, you'll be doing yourself a favor by picking this game up. And imagine this - this is just one of the very first games out for psp. Imagine what things will be like a year or two out!