Final Fantasy IV retains the original Active Time Battle System from the initial Super Nintendo release. Similar to the previous remake of Final Fantasy III on the Nintendo DS, the control of stylus is limited and optional in order to retain the same control input while allowing other players to use the Nintendo DS's unique touch control scheme. However, the remake features a new ability system known as the "Augment System", or the "Decant Ability System" (デカントアビリティシステム, Dekanto Abiriti Shisutemu) in the Japanese version. The system allows for certain character-only abilities to be transferred to other characters who did not have them in the original and previous re-releases of Final Fantasy IV. Up to three abilities can be transferred to temporary party members. When leaving the party, temporary characters will yield abilities of their own, the number of which is dependent on how many abilities they were given. There are also other abilities; some scattered around the world, and some that become available after certain story events. This new system entails another new feature: command menu customization. All commands in a character's battle menu, except the "Items" command, can be replaced with augments. This includes individual abilities that are ordinarily contained in a group (e.g. "Curaga" can be added directly to Rosa's command list, rather than only being accessible through the White Magic sub-list). The Augment System was devised to replace the system in Final Fantasy IV Advance where the characters that were temporary in the original version became playable again at a certain point, as the developers felt that this system changed the game too much.[5]
Other exclusive enhancements to the DS version of the game include Minigames. Unlike the main game, minigames are stylus-control only. Their function is to increase the power of Rydia's personal Eidolon, Whyt (ポーチカ, Pōchika, Pochika in the Japanese version), who takes her place in the battle line-up, and acts under computer control according to abilities assigned to him by the player. The minigames can be played in either single-player or wireless (not online) multiplayer modes. The game also features a New Game Plus.[6] This allows players to start a new game with certain enhancements, such as rare or secret items and equipment, carried over from a previously completed game. Certain other new features are only available in a New Game Plus, such as hidden bosses on the face of the moon and the summit of Mt. Ordeals. Because of the voice-acted scenes, Namingway cannot change any character's name as he did in the original game. After realizing this, he travels the world, changing his own name to fit each occupation he takes up. Examples of his name changes include "Mappingway" (charting the maps on the lower screen), "Campingway", and "Weddingway". Following Namingway around the world and engaging in his sidequest yields numerous rewards. With the removal of the limit on items that the player can carry, Fat Chocobo no longer stores items, and instead can be called on in order to access the new bestiary and the video and music player, as well as the Whyt minigames.