Fushigi no Dungeon: Fuurai no Shiren 4

The fourth installment of the Shiren the Wanderer subseries of the Mystery Dungeon franchise was developed specifically for DS and later ported to PSP.

This sequel to Shiren the Wanderer goes back to basics with the adventure being in one huge 36 level dungeon (with many indoor and outdoor levels) and Shiren's level resetting back to 1 on every dive into the dungeon. While they appear to have dropped the previous game's Dragon Orbs and the Monster Meat system, they've added some new tweaks including a Day/Night Cycle (day is standard Shiren fare but in the night players can only fight off the baddies with their very limited supply of Night Techniques since the monsters are immune to all standard attacks), Weapon/Shield Leveling (use a weapon or shield long enough and it will level up increasing its base value, enchant limit, and meldable ability slots), and somewhat related to the last feature, an ability to register favorite weapons and shields (basically pay an exorbitant amount of money so that even if the player falls or loses them, these favorite items will be waiting for them in the game's second village for them to pick up).