The X2 part of this PSP downloadable title is supposed to refer to the amount of content this retro RPG sequel boasts: twice as much as the original Cladun game. (Cladun itself stands for “classic dungeon”.) This sprite-based dungeon crawler is deceptively deep and 100% customizable right down to your main character. Just like a classic pen and paper RPG, you have to pick a face, a name, a character class (warrior, wizard, ranger, etc.), the whole spiel before you even get started.
You can create the rest of your team in the same way, however many teammates you want. There's not much point in having multiple characters of a single class, since this isn't your classic turn-based RPG, but a Zelda-style overhead view action-RPG that allows you to control only one character at a time.
The aspect I find most interesting about this game is the ability to use anyone you want as your main character, switching from sword-wielder to magic-user to archer before tackling any given level (actually, any character can use any weapon, but they only learn special skills for the preferred weapon of their class). There's a tremendous difference to your playing style if you are firing arrows, swinging a club, bearing a sword and shield, or wielding a magical staff.
Your teammates are not there just to switch up your playing style now and then. Using a magic circle, you can place all your secondary characters around your main character of the moment, allowing them to magically add strength and attributes to your actual controllable character through the equipping of artifacts. All of the characters in your magic circle will also die first, before the player-controlled character begins to lose health. They also gain experience for enemies defeated while they are part of the circle.
There is a story here, but it is minimal. It comes complete with Nippon Ichi's trademark skewed humour, à la the prinnies, and never takes itself too seriously. You can play dungeons over and over, gaining bonuses by completing them speedily, or focus on level progression. The use of your magic circle has a huge effect on how both your main character and sub characters level up, and character stats change differently depending on whether they are gaining experience as a sub-character in a magic circle or as the main character the player controls in the dungeon. Experience as both a sub-character and the main character are necessary for complete character growth.