iPhone games are built, for the most part, with quick gameplay in mind. Chances are you're waiting for a subway and you only have five minutes to sneak some playtime in. Therefore it makes sense that the AppStore is filled with match-three clones, simple shooters and arcade games. "Zenonia" is not one of those games.
At first "Zenonia" looks like 16-bit adventure games like The Legend of Zelda on the SNES. But the clean graphics hide the true nature of a surprisingly deep RPG. Like "Diablo," "Zenonia" has you traversing a large world map, completing quests, killing evil wildlife and leveling up your character. There's a skill tree and stats which you can boost depending on your play style, and there are three very unique character classes to kick your adventure off (the slow but powerful warrior, the magic-using paladin and the speedy and deadly assassin).
Glancing at the message boards, a rampant fan following shares strategies and character builds online, and everyone seems to be eagerly awaiting a patch with will fix the game's one weak point: a twitchy, not-super-responsive control pad. The patch is supposed to be out this week.
If you're sick of short, basic games on your iPhone, "Zenonia" is the deepest, most engrossing RPG I've found. And for $6, you're probably not going to find much better bang for your buck on the iPhone.