Great 3D graphics engine with standard turn-based japanese-style RPG combat. Extremely solid gameplay.
The combat system is utterly standard in every way. You'll get some weapons that will do extra damage to one creature type, but otherwise weapons are generic and ordinary. There' no armor or anything like that.
90% of the game is leveling up your "monsters" so that you can handle stronger monsters on the next island you will explore. That's not as tedious as it sounds because you have quite a bit of choice about what abilities your monsters will have (ice powers or fire powers) (attack bonuses or defend bonuses) as you mate them with other monsters. Once you combine 2 monsters to make a new one, you'll have to level up that new monster, so expect to quite a bit of level grinding in the game if you do a lot of combining of monsters. There no compelling reason to combine monsters -- you could beat the game only occasionally combining a few monsters.
The gameworld isnt huge (which is to be expected for a 3D game on a DS cartridge) but the islands are varied enough to keep you interested. There's several interior dungeons too, and they are small in size. Like the rest of the game, the dungeons are colorful and well-designed.
The game doesnt punish you much for making mistakes. If your team dies you lose half of your gold (you can store gold to avoid losing a lot of money). Otherwise, your team is resurrected for free and then you go back out for more combat.
The worst thing I can say about this great game is that it is basically a level-griding game. If that doesnt sound like fun, this isnt the game for you. But for those who like developing characters in a RPG-lite environment, "Jokers" is certainly worth a look.