Deep Labyrinth

From a first-person perspective, players must navigate through dungeons and environments in a 3-D world, battling enemies while searching for items, secret side areas and ways to unlock locked doors, whether with keys or magical spells. Both swordplay and sorcery are at the player's disposal, controlled using the Nintendo DS' stylus and touch screen, and the more frequently a player uses either means of attack, the stronger it will become. Players can also use shields to block and reduce damage from enemy attacks, or evade them with quick steps via circle strafing and an automatic lock-on system.

To cast magic spells, whose names are ancient Greek words (for instance, astrape for thunder and iaomai for healing), the player must trace out runic Kirie symbols across a 3 x 3 grid, using one unbroken stroke of the stylus over select squares in the grid. Spells cost mana and most spells must be learned either through leveling up or from reading Kirie slates that will teach particular spells. Players can only save their progress by talking to certain non-playable characters, and save points serve as checkpoints; should the player fall in battle from losing all health or getting hit by a death spell, unsaved progress is forfeited and the player must reload a previously saved game.

Both versions of the game contain a campaign story where a man is unexpectedly warped into a labyrinth several stories tall while talking on his cell phone. Starting from the bottom, in the deeper of two basement floors, he quickly picks up a sword and shield and battles his way through every floor to the top, seeking the secrets of this mysterious place, answers to why he is trapped there and the identity of a mysterious girl whose soul is trapped in a crystal. Depending on how quickly the player is able to dispatch the final boss at the top, he may or may not save this girl.

The Nintendo DS version has an extra, easier, scenario intended for casual players, in which the main protagonists are a boy and his pet dog, named Shawn and Ace (Shou and Alf respectively in the Japanese version) respectively. One summer afternoon, Shawn goes for a drive with his parents and dog, Ace, but the family car suffers a flat tire in front of an abandoned mansion. Ace is upset by something inside the mansion and leaps out of the car to investigate. Shawn's parents follow Ace, but fail to return.

Deep Labyrinth was developed by Interactive Brains, with Masato Kato writing the game's scenario and Yasunori Mitsuda composing its music. The game is billed as the first 3D RPG for Japanese mobile phones.

According to Nasaki Takeda, CEO and CTO of Interactive Brains, the mobile phone release of Deep Labyrinth was very popular, having been downloaded nearly 100,000 times prior to its North American DS launch.

In Japan, Famitsu gave the DS version a score of one eight and three sixes, for a total of 26 out of 40. Elsewhere, though, the port received "mixed" reviews according to video game review aggregator Metacritic.