Unlike other side-scrolling and belt-scrolling beat-em-ups of the time, Guardian Heroes features a multi-layer playfield (where players can jump between each of the three "layers" at any time using specific buttons, in similar fashion to the Fatal Fury series of fighting games). This allows players to evade attacks, focus on specific enemies, and perform special attacks using fighting game movements. The game is also known for its RPG elements (including experience point and skill point systems), competitive arena mode (where up to six players, either human or AI, brawl), and a branching campaign (including multiple endings, based on both path taken and karma, and a variety of unlockable characters for arena mode).
The game received a handheld sequel, titled Advance Guardian Heroes, for the Game Boy Advance in 2004. The original game later received an enhanced port for the Xbox 360 (via Xbox Live Arcade) on October 12, 2011, featuring enhanced HD visuals, rebalanced gameplay (including full widescreen support and new controls), updated dialogue, online drop-in multiplayer, and new game modes (including a survival mode and an expanded arena mode that doubles the maximum number of combatants to 12 online players).
The Guardian Heroes are a group of adventurers whose acquirement of a certain mythical sword makes them targets of the royal knights. After being warned of an impending ambush by an enigmatic knight named Serena, and fending off the first attack by the kingdom's military, the Guardian Heroes next course of action is decided by the player through the game's branching routes system. While there a variety of paths to follow, they all eventually lead to Kanon, the sorceror who secretly controls the kingdom.
Kanon reveals some startling revelations about the history of their world, and once again the player must decide the Guardian Heroes' fate. Their choices eventually lead to either a confrontation with the Celestial beings who played a significant hand in human history, their Subteranean rivals, stopping the mechanical army created by Kanon, a surprise threat from a scheming opportunist or a last battle in the Heavens with a major rival.
- STR : Physical attack strength and knockback range.
- VIT : Total amount of HP.
- INT : Magical attack strength and size.
- MEN : Total Amount of MP and rate of recovery.
- AGL : Movement, physical attack and spellcasting speed.
- LUC : Modifies damage and defence, chance of random damage and defence bonuses. Also governs Nicole's spell selection.
An ex-knight, Samuel Han is the game's obligatory warrior character. Han carries a large sword and starts with the highest attack stat in the game. He can easily be levelled up into a physical killing machine, but initially suffers from low agility and can only use a single spell. Taking a certain path in story mode will earn Han a sword which gives him a huge stat boost.
Randy M. Green is an apprentice sorcerer who fights with a staff and travels with a rabbit named Nando, who fights alongside him. Randy has a wide range of spells at his disposal, but starts off with poor vitality. He has a few useful multi-hit attacks, however, and with a few stat increases he can easily hold his own in combat.
Ginjirou Ibushi is a questing ninja searching for the sword Muramasa. With high agility and a good selection of thunder spells, his quick attacks and use of magic make pulling off combos very easy.
As the game's cleric, Nicole Neil is physically weak, most of her attacks being virtually useless. She makes up for this by being the only character with a healing spell, and possesses a useful barrier spell which pushes back and damages enemies. Nicole is also unique in that she is the only character whose spell selection is dictated by her LUC stat.
A rebel knight, Serena Corsair is only playable once the story mode has been played through once. She starts off with completely even stats and no real strengths or weaknesses allowing for easy customisation, and possesses a wide range of attacks which can become quite powerful, along with a decent selection of ice magic.
Initially, players only start with the four main Story Mode characters above (and the Undead Hero). By defeating enemies (or hurting civilians) in the Normal or Hard difficulties of Story Mode, players can unlock these characters for use in Versus Mode. Serena is also unlockable for Versus Mode once she is unlocked for Story Mode. A special variation of Han, called "Han the Hero", can be unlocked for Versus Mode once he defeats the Undead Rogue. There are a total of 44 playable characters in this mode.
Each character has their own unique stats and movesets, with some characters (such as the civilians) having little-to-no abilities.
- Civilian Blimp
- Civilian Child
- Civilian Elder
- Civilian Wimp
- Civilian Woman
- Earth Spirit
- Golden Silver
- Golem God
- Proto Silver
- Royal Blade
- Royal Knight
- Royal Mage
- Royal Mech
- Royal Purger
- Sky Spirit
- Sky Warrior
- Super Zur
- Undead Rogue