The big problem with Lostmagic is that the first hour of the game is a painful exercise in bashing your head up against the brick wall of figuring all this stuff out for yourself. The game does an OK job of explaining the basics, but it's so incredibly tough to actually apply them effectively that you're going to have to try and try again just to survive. It's the difference between being told how to drive a car and actually taking to the road.
Even if you make it through that trial by fire, you'll still find the game is a challenge. In fact, from the kid-friendly anime graphics to the simple spell-casting, the game seems like it should be easy. After the first hour or so, things open up - you can fight random battles, increase Isaac and your monsters' powers, as well as figure out better strategies to deal with what the game throws at you. That's when it truly becomes addictive.
Lostmagic is notable for being one of the few games that currently works with Nintendo Wi-Fi Connection. You can duel using the character you raised yourself - handicapping will keep you from getting smoked by someone at a higher level. If that doesn't sound appealing, you can duel with super-buff characters with full lists of spells and monster units. This includes the game's bosses, once you defeat them. Either way, it's hard to get really interested in this mode unless you tackle it once you've played a hell of a lot of the single-player game, and find a friend who's done the same. Even then, you're likely to run into frequent stuttering pauses in the gameplay if the internet connection isn't rock-solid.