The gameplay features both side-scrolling and "3D" (third-person, behind-the-shoulder) segments, as well as open-world exploration. It also features hack & slash, real-time combat, in both the side-scrolling and third-person segments, making it the earliest example of third-person hack & slash combat. In the third-person dungeons, enemies appear at predetermined locations, with the third-person combat involving the player attacking the enemy and moving left and right to dodge, a precursor to Crossed Swords on the Neo Geo. There is also a third-person jump attack, a precursor to The Legend of Zelda: Ocarina of Time.
At the time of the game's release, there was a debate as to whether Getsu Fuuma Den was influenced by Namco's game Genpei Toumaden; at the time Konami vigorously denied it, but years later the producer of the game admitted it was influenced by Genpei Toumaden in a Dorimaga interview. Despite the influence, Getsu Fuuma plays very differently, with a greater emphasis on open-ended exploration and RPG elements as well as third-person combat. Sega's Kenseiden for the Master System appears to have been influenced by Getsu Fuuma Den.
In Castlevania: Harmony of Despair, there was an entire stage based around Getsu Fuuma Den released as downloadable content. Also released was Getsu Fuma (sic) as a playable character. The stage, titled The Legend of Fuma, is priced at 240 Microsoft points ($3.00), while the character is priced at 160 Microsoft points ($2.00).
Getsu Fuuma Den has heavy "adventure" elements; the player moves Fuuma around on a world map to enter the various hellish places he must pass through on his journey to reclaim his family's lost heirloom and to defeat the overlord of the demons, Ryuukotsuki. In addition, there are various other locations to stop at on the world map, from shops to locations where spooky demons will give Fuuma hints as to what to do.
The side-scrolling portions of the game are simple to control: Fuuma can move left or right, jump, and attack. Enemies that collide with Fuuma will deplete his life in a typical fashion. Some stages feature objects that will block Fuuma's path (I.E., an iwakura). These can generally be destroyed by striking them with an attack. The beginning and end of most of the side-scrolling stages are indicated by tori style gates.
Other portions of the game are from a sort of third-person view: In these parts, Fuuma must navigate maze-like corridors to reach one of any number of objectives (either an item or a way out, generally!) Fuuma can strike with his sword in these portions as well as jump, but obviously the perspective is different and play style must be adjusted accordingly!
Many items can be picked up Fuuma's quest to aid him on his journey. These are items that are used in battle.
- Soul: These are dropped by some enemies in the side-scrolling stages. They increase Fuuma's life; the amount depends on the enemy.
- Gold bag: These too are dropped by some enemies in the side-scrolling stages. The amount of gold received for a pickup depends on the enemy.
- Straw Man: A rare item in the side-scrolling portions, it gives the player an extra life.
- Mamoridaiko (Drum of Protection): Fires the kanji "力" (chikara, or "strength") at enemies when used.
- Iwa no ken: The basic sword of Fuuma. It can be used to break rocks in some stages.
- Mashou no koma: A demon's top. Allows for a spinning attack.
- Shuriken: The famous "throwing stars". Fuuma throws three shuriken per attack.
- Noroi no bakuyaku: Cursed explosives. When used, it splits in to several "bursts" that travel along surfaces.
- Noroi no Koromo: Cursed clothing. Become temporarily invincible when used. However, the item is consumed after using it.
- Hadouken: The family sword. Fire huge waves of energy with each strike.
These items have a supporting role for Fuuma.
- Charm: Temporarily raises defense when used. It is consumed with use.
- Life potion: Restores Fuuma's life. Consumed when used.
- Jyuumon no akadama: A red spell sphere. It completely destroys enemies in the third-person segments with a single use. However, it is consumed when used.
- Jyuumon no aodama: A blue spell sphere. It destroys all enemies on screen in the side-scrolling portions, but is consumed with use.
- Candle: Lights up dark portions of side-scrolling caves or the third-person dungeons.
- Mamoridama: "Protection sphere". Makes three fireballs appear and orbit around Fuuma, protecting him from enemies. They are destroyed after a couple of hits and the item is consumed.
- Compass: Makes the third-person segments more navigable.
- Kimenhu: A demon's mask. Getsu can't go to some of the places where major bosses are located without these! But the ghosts who have them can be really difficult to negotiate with, in more ways than one...
In the year 14672 of the "Magic Calendar", the demon king Ryuukotsuki (龍骨鬼/"Dragon Bones Demon") emerges from the underworld and brings Hell to Earth! Humans face extinction and demons roam the world with impunity. The three Getsu brothers, the "Getsushisan Kyodai" who had ruled Earth before the coming of the demons, stand virtually alone against the hordes of the underworld. With his two elder brothers slain in battle, it falls to Getsu Fuuma alone to destroy the demon armies and avenge his fallen brothers by destroying Ryuukotsuki himself! But before he can do that, he must reclaim his family's heirloom, the "hadouken" (波動剣/ wave sword).
Getsu Fuuma: The protagonist, he is a heroic swordsman who is virtually a demigod in nature. He has a running speed of over 60 km/h ( a little under 40 miles an hour) and can easily lift over 180 kg (around 400 pounds).
Ryuukotsuki: The demon lord. He killed Fuuma's brothers and stole the Hadouken from them, the only sword deadly enough to harm him. He has fragmented the hadouken and hidden the parts in various locations under the protection of his top minions.
Getsu Fūma Den (月風魔伝), Hardcore Gaming 101