A battle scene from the Super Nintendo version of the game: the party engages a Blue Dragon on the Moon

In Final Fantasy IV, the player controls a large cast of characters and completes quests to advance the story. Characters move and interact with people and enemies on a field map, which may represent a variety of settings, such as towers, caves, and forests. Travel between areas occurs on a world map. The player can use towns to replenish strength, buy equipment, and discover clues about their next destination.^[4] Conversely, the player fights monsters at random intervals on the world map and in dungeons. In battle, the player has the option to fight, use magic or an item, retreat, change character positions, parry, or pause. Certain characters have special options.^[4] Player characters and monsters have HP or hit points (represented by a numerically based life bar); attacks reduce hit points until none are left, at which point the character faints or the monster dies. If all characters are defeated, the game must be restored from a saved game file.^[4] The player can restore the characters' hit points by having them sleep in an inn or use items in the party's inventory, such as a Potion. Equipment (such as swords or armor) bought in towns or found in dungeons can be used to minimize received damage or increase damage inflicted on monsters.^[4] The player can choose whether characters appear on the front line of a battle or in reserve. A character's placement impacts distribution of damage received and inflicted.^[4] The game's story is linear—the player can usually advance the game through only one path, although limited side quests are available.^[8]

Final Fantasy IV introduced Square's Active Time Battle (ATB) system designed by Hiroyuki Ito, who was one of the battle designers with Kazuhiko Aoki and Akihiko Matsui, which differed from the turn-based designs of previous RPGs.^[9] The ATB system centers around the player inputting orders for the characters in real time during battles.^[10] An important precedent, ATB was used in many subsequent Square games. Each character is balanced through certain strengths and weaknesses; for instance, a strong magic user may have low defense, while a physical fighter may have low agility. Like other Final Fantasy games, characters gain new, more powerful abilities with battle experience. Magic is classified as either "White" for healing and support; "Black" for offense; or "Summon" (or "call") for summoning monsters to attack or carry out specialized applications.^[4] A fourth type—"Ninjutsu"—consists of support and offensive magic and is available to only one character. Magic users, who account for eight of twelve playable characters, gain magic spells at preprogrammed experience levels or fixed story events. The developers have balanced point gains, items, and rewards to eliminate long sessions of gaining levels.^[5] Due to the Super Nintendo's greater processing power, Final Fantasy IV contains graphics improved over past Final Fantasy titles and concurrent Super Nintendo games.^[11] The game employs the Super Nintendo's Mode 7 technology to give enhanced magic spell visuals and to make airship travel more dramatic by scaling and tilting the ground for a bird's eye view.