I am a green squirrel. At least, that's what Pokemon Mystery Dungeon decided after asking me a series of multiple choice questions a la Ultima. The squirrel is called a "Bulbasaur" for some reason. But really he's just a green squirrel who eventually learns to do things like shoot long-range grass attacks and puff out stinky pink smoke. Actually, maybe he's a green skunk. It's better not to think about it.

Which isn't hard to do with Pokemon Mystery Dungeon. The emphasis is clearly on the 'Mystery Dungeon' part of the title, with the 'Pokemon' being easy enough to ignore if you're not into the kiddie culture of it all. This is one of those rare “kiddie” titles where the licensing doesn't upstage the gameplay (the superlative Yu Gi Oh Ultimate Masters 2006 for the Gameboy Advance is another). Yeah, sure, you're playing with Pokemon. But more importantly, you're playing a surprisingly sophisticated Roguelike.

If you're not familiar with the genre of Roguelikes (obligatory Wikipedia link explaining what Roguelikes are - ed.) -- as is clearly the case with some reviewers of Pokemon Mystery Dungeons -- the basic idea is that you're doing a turn-based crawl through a randomly generated dungeon, one level at a time. It's a long tradition that stretches from Rogue (1980) to Nethack (1987) to Angband (1990) to the sadly overlooked Nightmare of Druaga (2004), and arguably including evolved forms Diablo and the upcoming Hellgate: London. As with any RPG, the idea is to level up your character, but also to explore as far as you can. In a Roguelike, the randomness smoothes out the undisguised grind, since everyplace is someplace you've never seen before. So what if it's just some scripting algorithm dropping halls, rooms, and that all-important staircase to the next level? As rote as they may be, these dungeons are like snowflakes.

Until Diablo went real time and visually lush, games like Rogue and Nethack were drawn with ASCII characters, with your avatar being an @. They relied heavily on statistics, and boiled down to little more than spreadsheet front-ends for the perennial gamble of whether you should press on or go back to town to recover and stock up. But in Pokemon Mystery Dungeon, instead of playing as an @, you're a cute little animal. You still control a single character, Rogue-style, but you can bring with you up to three other computer-controlled characters. Think of them as your pack of little dogs.

The game's basic progression is a matter of developing various Pokemon (one of the things I've recently learned is that the plural of “Pokemon” is, in fact, “Pokemon”). First you have to collect them. You buy plots of land that are the native habitats of specific Pokemon, at which point there's a chance that type of critter will surrender and join your team during a battle. This makes it worthwhile to "harvest" lower level dungeons for recruits. This collection dynamic -- "Gotta catch 'em all!" -- is a basic fact of the Pokemon condition and Mystery Dungeons is no exception.

Pokemon don't wear armor or wield swords. Duh. So there's not much in the way of traditional loot. Instead, the hook for the RPG inclined is building up your favorite Pokemon's repertoire of moves, which tend to be attacks, buffs, or debuffs. As the little fellas level up, they'll learn new moves. You'll also find single-use discs that will teach a new move. Since a critter can only "remember" four moves at a time, and since there's an underlying system of attack type vs. Pokemon type, choosing moves serves as a substitute for the traditional RPG inventory.

Also, since all the Pokemon but your main character are computer-controlled, there's an IQ system. Pokemon start with a few basic parameters, called IQ Skills, such as being told to pick up stray items or focus on using special moves. As they get smarter, they learn new skills, such as matching moves against Pokemon types, targeting the most powerful enemies, or avoiding traps. But the only way they get smarter is if you feed them jelly beans, which you can find in the dungeons. Different Pokemon prefer different jelly beans, so the randomized loot will force some choices. Do you save that gold jelly bean in case you find a psychic Pokemon, or do you just give it to the flying Pokemon you've been grooming to be your sidekick?

In the game fiction, the excuse for the dungeoneering is that you're forming teams to go down into dangerous areas and rescue fellow Pokemon. Okay, fine, I'm all, 'whatever'. But where this makes more sense is in the way multiplayer works. When you die and respawn back in town, you lose your money, half your inventory items, and whatever progress you've made towards the bottom of the dungeon. But instead of respawning, you can copy an elaborate password, which another player can input into his game. The password then generates a rescue mission for that player. Once it's accomplished, your rescuer gives you the A-OK password and you can use it to revive where you left off, without any penalty. Then you can send a thank you reward pass code back. Pokemon helping Pokemon are the luckiest Pokemon in the world.

There's a storyline, but it's not the entirety or even the meat of the game. It gets a little weird, if you can be bothered to read the cutscenes. The world of Pokemon is plagued by a sort of Original Sin analog. So you’re a Christly figure, a human-made-Pokemon, come to redeem them and then leave them, ascending into heaven just in time for the credits to roll and...no, wait, false alarm. It's an ‘I Will Be With You Always’ message, every bit as unsubtle but probably less intentional than The Chronicles of Narnia. Of course, it's not until all that stuff is out of the way that Pokemon addresses the issue of evolution. This will all make sense in the end.

In fact, it's hard to truly appreciate Mystery Dungeon until after you've slain the main foozle (or "caused him to faint", as it's portrayed in this child-friendly mythos) and saved the world from a comet that suddenly appears in the last act for no good reason. This is when Mystery Dungeons truly stops being a Pokemon game and turns into something far more substantial: a freeform Roguelike for your Nintendo DS or Gameboy Advance that offers raw unadulterated leveling. Because now you're free to dungeon crawl unfettered by motivation or plot. You can even directly control the Pokemon of your choice or try your hand at a truly Nethack style single-character leveling challenge. Now Mystery Dungeon is as challenging and long-lived as you want it to be.