North American cover art
Etrian Odyssey, released in Japan as Sekaiju no Meikyuu (世界樹の迷宮 Sekaiju no Meikyū?, literally "Labyrinth of the World Tree"), is a 3D dungeon crawler role-playing video game by Atlus for the Nintendo DS.
Drawing comparisons to titles such as Wizardry and The Bard's Tale, Etrian Odyssey challenges players with exploring and mapping a vast dungeon. Players navigate through the dungeon in fixed increments. Time passes only when an action is taken, causing movement, random encounters, and combat to all be entirely turn-based. The game uses a first-person view to present the dungeon using a combination of relatively simple 3D computer graphics for environments and single-frame 2D sprites for enemies.
Etrian Odyssey requires that players maintain their own map by annotating (with the stylus) a small map displayed on the DS's touchscreen. The player is free to map accurately or haphazardly. However, the player cannot draw their own symbols, and must instead use the game's limited set of pre-designed symbols. The game also limits the number of symbols that can be used for each level map.
In addition to normal random encounters, the player must overcome "FOEs" (Field On Enemies), which are exceptionally powerful monsters which wander around the dungeon in much the same way as the player's party, advancing whenever the player does. The AI of FOEs varies, but most will wander the dungeon in a set circular path until they sense the player's party, after which they will move directly towards the party. If the player encounters an FOE in an area with multiple FOEs, it is possible for a second or even third FOE to join the battle if it reaches the party before they defeat the first one.
Like most early RPGs, Etrian Odyssey uses custom characters from a number of different character classes. While only five characters can be in the party at a single time, a much larger number can be created and kept in waiting back at the "guild hall". Characters can be switched in and out of the party when in town, so if a given specialty is needed for a specific obstacle, the party can be tailored appropriately. The player allocates skill points to specific skills during level advancement.
The development team within Atlus was led by Kazuya Niinou who also directed the development of Atlus' first in-house game for the DS, Trauma Center: Under the Knife. The game features character designs by Yuji Himukai, monster design by Shin Nagasawa, a story by Shigeo Komori, and FM-like music by Yuzo Koshiro.
The game was originally to be released internationally as Yggdrasil Labyrinth, but was renamed to avoid any possible confusion with Yggdra Union (a game published in North America by Atlus a year earlier) or Deep Labyrinth.
Media Create/Famitsū reported that Etrian Odyssey had sold 119,584 copies in Japan as of July 1, 2007. Atlus' own July 2007 investors report listed US sales of the title at around 30,000 units, roughly 2 months after release.
Although the title was recognized as accomplishing its goals (in terms of presenting a very classic RPG experience), it was noted that this greatly limits its appeal to a certain "hardcore" demographic. The IGN review noted, "[...] if you gave this game to ten players you may find one or two in the group that truly enjoy it". GamePro concurred, remarking "Ultimately, this one is for fans of the genre and not for the short-on-time".
Most reviews noted that those who enjoy rigorous dungeon crawls or fondly recall similar titles from years past may greatly enjoy the game. 1UP.com summarized this sentiment by concluding "Etrian Odyssey will definitely appeal more to the OCD'd than the ADD'd, and its punishing difficulty and very deliberate pacing may turn off younger gamers who grew up on flashier roleplayers. But it offers a real sense of wonder and a sense of accomplishment -- feelings missing from far too many modern games". N-Europe awarded the game an 8/10 score, though criticised its lack of story and the fact that it is "too old school for some".
Etrian Odyssey sold 32,511 copies in its first week of release in Japan. 
Towards the end of 2007, Atlus announced a sequel to Etrian Odyssey. It was reported that the game would feature 12 job classes and that Yuji Himukai, Makoto Nagasawa and Yuzo Koshiro would reprise their roles, with Shigeo Komori taking on the role of director. All of character classes are reused, along with three new classes: Beast, Gunner, and War Magus. The mapping system was improved, with new symbols that can be added to the map for more detailed and accurate maps.
The sequel was released on February 21, 2008, in Japan and in North America on June 17, 2008. There are no plans to release the game in the European region.
In early December 2009, the third installment in the series, titled "Sekaiju no MeiQ 3: Seikai no Raihōsha", was announced in Japan. This game features ocean exploring in addition to dungeon exploring, both with the familiar mapping system. In addition, the classes from previous games are removed in favor of all-new classes, including Royalty, Monk, Hoplite, Ninja, and Buccaneer. The game was released in Japan on April 1, 2010, and in North America on September 21, 2010, under the title Etrian Odyssey III: The Drowned City. The game has not been released in the European region.
Legends of the Titan is the first Etrian Odyssey title for the Nintendo 3DS. This game features a traverse able overworld in addition to dungeon exploration. The classes in this game are a mix of old and new, with old classes including the Landsknecht, Medic and Fortress (formerly Protector), while new ones include the Sniper, the Arcanist, and the Imperial. It was released in Japan on July 5, 2012, in North America on February 26, 2013, and in Europe on August 30, 2013.
Etrian Odyssey Untold: The Millennium Girl is a semi-remake of Etrian Odyssey which features animated cutscenes and voice acting. It was released in Japan on June 27, 2013, in North America on October 1, 2013 and in Europe on May 2, 2014.
Persona Q: Shadow of the Labyrinth is an Etrian Odyssey-esque game for the Nintendo 3DS starring the characters of both Persona 3 and Persona 4. Instead of a customizable party, you have preset characters that learn skills linearly like in the Persona games. Fusion is also possible through the use of sub-Personas that can be equipped to the characters to gain extra skills and an HP/SP boost at the start of a battle. When striking an enemy weakness in combat, the character will be boosted, allowing them to move first in the next turn and use any skill for free. However, if a character is attacked while boosted, they will lose their boosted status. Everything else is virtually identical to the other Etrian Odyssey games, including map making and FOE's. The game was released on June 5, 2014 in Japan, November 25, 2014 in North America, November 28, 2014 in Europe, and December 4, 2014 in Australia. The game marked the first time a Persona title has released on a Nintendo platform.
Etrian Mystery Dungeon is a cross over of the Mystery Dungeon and Etrian Odyssey series. Instead of the first-person view of the dungeon, it's been changed to a third-person angle where you can see everything at an aerial view.The original Etrian Odyssey's game system has been changed into the Mystery Dungeon's turn-based strategy where the player is allowed a period of analysis before deciding on a move to make, committing to it, then waiting for the opponent or enemy to make their turn. This is followed by the next round of play where the player makes their turn again. The game was released on March 5, 2015 in Japan and April 7, 2015 in North America. It is also planned for release in Europe on September 11, 2015.
Etrian Odyssey 2 Untold: The Fafnir Knight is a remake of Etrian Odyssey II: Heroes of Lagaard in the vein of Etrian Odyssey Untold: The Millennium Girl. It features a story mode with a set of characters, cutscenes, an orchestrated soundtrack and many new features. It was released in Japan on November 27, 2014. The game is set for release in North America on August 4, 2015, and in Europe on February 12, 2016.
- Meunier, Nathan. "Etrian Odyssey Review". Cheat Code Central. Retrieved 2008-08-07.
- Dobson, Jason (2007-03-21). "Interview: Atlus' Nich Maragos On Etrian Odyssey". Snackbar Games.
- Fitch, Andrew (2007-05-15). "Reviews: Etrian Odyssey". 1UP.com.
- Riley, Adam (October 1, 2007). "C3 News :: Nintendo Wii/DS Reviews – Famitsu Rates Wario, Excite Truck & More". Cubed3.com. Retrieved 2008-12-24.
- Magrino, Tom (2007-05-29). "Etrian Odyssey for DS Review". GameSpot.
- Bozon (2007-05-16). "IGN: Etrian Odyssey Review". IGN.
- Dalthien. "Japan DS/PSP Sales Charts". Retrieved 2008-08-12.
- "2007年7月期 決算説明会資料" (PDF). Atlus. Archived from the original (PDF) on October 8, 2007. Retrieved 2008-08-12.
- Glasser, AJ (2007-05-15). "Review: Etrian Odyssey for DS". GamePro. Archived from the original on 2007-05-17.
- Penny, Steven (2008-08-20). "DS Review: Etrian Odyssey". N-Europe. Retrieved 2008-08-28.
- Ishaan (2012-07-11). "Siliconera: This Week In Sales: Anarchy Reigns In The Midst Of An Etrian Odyssey".
- IGN Staff (2007-10-03). "Etrian Odyssey Sequel Announced". IGN.
- Madden, Orla (2012-11-21). "Etrian Odyssey IV: Legends of the Titan Dated For North America". Nintendo Life. Retrieved 2011-11-22.
- Whitehead, Thomas (2013-07-16). "Etrian Odyssey IV Confirmed for European Release on 30th August". Nintendo Life. Retrieved 2013-10-06.
- Mallory, Jordan. "Etrian Odyssey Untold: The Millennium Girl maps out 3DS this fall". AOL Tech. Retrieved 2013-06-17.
- Collier, Shawn. "Stand Next To Royalty With Etrian Mystery Dungeon's Sovereign". engadget. Retrieved 2015-03-17.
- Romano, Sal (April 14, 2015). "Devil Survivor 2: Record Breaker and Etrian Mystery Dungeon coming to Europe this fall". Gematsu. Retrieved April 15, 2015.
- Romano, Sal (April 14, 2015). "Etrian Odyssey 2 Untold coming to Europe in early 2016". Gematsu. Retrieved April 15, 2015.