Gameplay

The Golden Sun series features a contemporary presentation of the traditional console role-playing game formula, where the player guides a cast of four characters as they journey through a fantasy-themed game world, interact with other characters, battle many monsters, acquire increasingly powerful magic spells and equipment, and take part in a building, predefined narrative. While many actions the player takes are compulsory, the Golden Sun games often allows the player to complete certain objectives out of order, and to visit previous locations, which can advance minor story elements.

Much of the games' time spent outside of battle takes place in dungeons, caves, and other locales involving many puzzles integrated into their layout. One must push logs into rivers in order to cross them, shift the track of a mine cart to access new areas, and a host of other activities in order to get from point A to point B and progress through the story and game world. Many of these puzzles revolve heavily around the usage of the games' resident form of magic spells, Psynergy ("Energy" in the japanese version), requiring the player to find items that grant the bearer new forms of Psynergy in order to accomplish tasks.

Both successful exploration of the games' world and victory in the games' battles are heavily dependent on the strategic usage of the hundreds of Psynergy spells available. Whereas many other RPGs limit the usage of their forms of magic to battles as offensive and defensive measures, Psynergy spells can be used both for battle and for solving puzzles in the games' locales. Some types of Psynergy can only be used in combat; conversely, many spells are only used in the games' overworld and in non-battle scenarios. At the same time, some Psynergy spells can also be used in both situations; for example, the Whirlwind spell that can be used to damage enemies in battle is also used out of battle to clear away overgrown foliage that may block the player's path. Psynergy comes in four elements: Venus (Manipulation of rocks and plants), Mars (Revolving around fire and heat), Jupiter (Based on wind and electricity), and Mercury (Concerning water and ice). The player gains more and more Psynergy spells as the game progresses, either through leveling up or acquiring and equipping (using) special items, and with each "utility" Psynergy spell the party gains access to more and more locations and secrets hidden within the game world. Players may return to previous locations in the games to finish off puzzles which they could not solve earlier because of the lack of a specific Psynergy spell.

Battle
The Golden Sun series contains both random monster encounters, featuring randomly selected enemies, and compulsory battles involving set enemies, which advance the story. When a battle begins, a separate screen is brought up where the player's party and enemy party are on opposite sides, facing off. During a battle, the characters and the background rotate to give a pseudo-3D effect.

The gameplay in relation to Golden Sun’s battle mode is similar to traditional console RPGs. In each battle, the player is required to defeat all the enemies by using direct attacks with weapons, offensive Psynergy spells, and other means of causing damage, all while keeping the player's own party alive through items and supportive Psynergy that restore life and supplement defense. If the player's entire party is downed by reducing their hit points to zero, it is considered "Game Over" and the party is returned to the last Sanctuary that the player visited and suffers a monetary penalty. The successful completion of a battle yields experience points, coins, and sometimes items.

In addition to the main game itself, there is also a competitive battling mode accessible from the menu screen. Here players can enter their currently-developed team from their saved game files into an arena environment where they can battle increasingly difficult CPU-controlled enemies or other players head-to-head to see which of their team setups are stronger. In both cases there are no rewards or punishments for winning or losing.

Djinn system
One of the most important features in the Golden Sun series is the collecting and manipulation of magical creatures called Djinn. Djinn (Singular: Djinni) can be found scattered in hiding throughout the games, for each of the four elements and likewise for allocation to each character. The Djinn form the basis of the games' statistic enhancement, as well as the system that dictates the character's Psynergy capabilities. Attaching different Djinn to different characters modifies that character's class, modifying hit points, Psynergy points, and other stats, as well as what Psynergy the character can perform.

In the games, Djinn can either be "turned on" ("Set") or "turned off" ("On Standby"). When a Djinni is "Set" to a character, that Djinni exerts influence on that character's class (and therefore, his or her statistics and Psynergy collection) relative to both the character's innate element and that of the Djinni's. As there are seventy-two Djinn encompassing the four elements that can be mixed and matched to the eight characters in seemingly any manner, a large array of possible class setups for all party members are potentially available, allowing a variety of combat options (in the original Golden Sun there were only twenty-eight Djinn and four characters).

In combat, a player can use a Djinni during that character's turn. Each Djinni has its own special ability which can be invoked during combat. These abilities can include (but are not limited to) enhanced elemental attacks, buffing or debuffing spells, healing/restoration spells, and other, sometimes truly unique effects. After a successful invoke, the Djinni shifts to "Standby" mode until it is "Set" on the character again. While in standby, the Djinn do not contribute to character classes, but can be used for Summon Sequences, where the player summons a powerful elemental monster. This is the series' most powerful method of attack, and also the riskiest, as it requires Djinn to be on Standby and therefore not be available to bolster the statistics of whatever character the Djinn are on. Once a Djinni on Standby has been used for a Summon Sequence, it must take any number of turns before it restores itself to Set position on a character. There are sixteen Summon Sequences in Golden Sun, four for each element, and thirteen "multi-elemental" summons are introduced in Golden Sun: The Lost Age. Each single-element Summon Sequence takes between one and four Djinn of the same element on Standby while multi-elemental summons could require anywhere from one to nine Djinn each from two different elements.