Pokémon Mystery Dungeon: Explorers of Sky is an enhanced version of Pokémon Mystery Dungeon: Explorers of Time and Explorers of Darkness released for the Nintendo DS in 2009, developed by Chunsoft and published by The Pokémon Company and Nintendo. As a sister game, and sometimes referred to as the definitive edition to the aforementioned games, additional features include the addition of the missing Generation IV Pokémon, further character development for a few side characters in content known as Special Episodes, and a few quality of life improvement for options, items, and other gameplay related features.
In terms of gameplay and premise, Explorers of Sky is largely similar to its predecessors, where a human-turned-Pokémon joins an exploration team, explores shifting dungeons, and fights hostile Pokémon through turn-based combat. The three games had accumulated worldwide sales in excess of 5.9 million copies in 2010, then 6.37 million copies after 2010. Upon its release, the game received mixed reviews from critics, in opposition to the fans' reception which was notably more positive, with many considering it a cult classic and the best game in the Mystery Dungeon series overall.
Gameplay
Serving as a sister game to Explorers of Time and Explorers of Darkness, a lot of new content was added in Explorers of Sky. As with its predecessors, the game follows the story of a human who is mysteriously transformed into a Pokémon, determined by a personality test at the game's start-up. Along with the starters from the previous game, five more are included as playable choices; Phanpy, Riolu, Shinx, Eevee, and Vulpix. Some, however, are only available to certain genders; Eevee, Skitty, and Vulpix are always female, while Riolu, Phanpy, and Shinx are always male. Moreover, 2 starters, Munchlax and Meowth, were removed from the playable roster and can only be picked as the partner.
New features
Lookalike items will start to appear early in the game; they have different effects from their original counterparts, and are distinguished by having a letter swapped or changed in its name (for example, while an Oran Berry heals 100 HP to its eater, an Oren Berry deals 10 damage). A new location appears in the only town during the story's progression named Spinda Café. It serves as a location to make drinks, recycle items, find new optional dungeons, obtain rare items and new missions, and see team members and recurring Pokémon hanging around. After completing the game's main story, the remaining Generation IV Pokémon that were not present in Explorers of Time and Explorers of Darkness, for example, both forms of Shaymin, the Origin form of Giratina available only for a few dungeons, and Arceus in the form of a statue in Destiny Tower, have returned since their in-game debut in Pokémon Platinum, which was released the year after the original games.
Throughout the entire game, the player is able to unlock music tracks in the Sky Jukebox, which allows them to play the game's entire soundtrack. This feature was recycled in the Nintendo Switch and Steam port of Shiren the Wanderer: The Tower of Fortune and the Dice of Fate in 2020, then for its smartphones port in 2022.
Explorers of Sky expands on the plot of Explorers of Time and Explorers of Darkness. One such is the event Pokémon Shaymin, located in a new location called Shaymin Village, and a new side story for Shaymin available after finishing the main story and graduating from the Guild. One of the new locations, Shaymin Village, along with its dungeon, Sky Peak Mountain Path, references Mystery Dungeon: Shiren the Wanderer and its main dungeon Table Mountain, as the progress from a village to the top of the mountain, checkpoints spread throughout the main dungeon, and a boss at the mountain's peak function equally in both games.
Through completing the main storyline of Explorers of Sky, five new Special Episodes will be gradually unlocked at certain points of the game which add unique stories expanding on side characters of the game, and explores the background of several other characters, sometimes new to the plot. They involve playing as the specified characters of the episode as opposed to the player's protagonist and partner; namely Bidoof, Wigglytuff (as Igglybuff), Sunflora, Team Charm (as Lopunny), and Grovyle.