It won't make you say wow, but visually, Monster Kingdom is pleasant to play in. We're particularly fond of the fantastic art direction. As if the eye candy wasn't enough, Monster Kingdom has a great soundtrack, devised by top-caliber composers. The tunes are varied, catchy, match the settings, and show off the PSP's sound system.
Monster Kingdom doesn't have the depth or polish of a Pokemon title, so on another console or portable with an impressive RPG roster, we'd score it the same, but might not recommend it so heavily. Here on PSP, where there's sadly less from which to choose, Monster Kingdom is a flawed, but enjoyable creature.