When control of the series transferred back to Koji Igarashi, his team would work on the Game Boy Advance's next Castlevania title after Circle of the Moon and move on to the following game hastily. With poor sales and critical reaction, Castlevania: Harmony of Dissonance hasn't received the same acclaim as Konami Computer Entertainment Tokyo's later work, Aria of Sorrow and the Nintendo DS Castlevanias. It's undeniably easy, the story isn't original or even that important to the overall timeline, and it's pretty blatantly rooted in Symphony of the Night, but this is a truly fun experience with haunting environments, enemies, and overall tone.
Again as with previous entries a friend of the protagonist is manipulated by Dracula, eventually giving rise to a vaster, darker plan than anyone could have predicted - save for the player. In this case it's 50 years after Simon Belmont defeated Dracula and now Juste Belmont, his grandson, also hunts for the Count's relics as chosen descendant of the Belmont clan. His friend Maxim Kischine appears to him for the first time since Maxim left for training 2 years before, without any memory of his training other than that Lydie Erlanger, the childhood friend of both, has been kidnapped. They travel to a strange castle where the two split up in search of Lydie. But something is strange about the castle, as if there's more to it, something else under the surface - and how literally so! The plot isn't anything new, the characters' personal motivations being pretty simplistic and the overall outcome easy to see in advance, but the confusion surrounding the castle's secret enhances that aspect of the gameplay and makes it that much more satisfying.
Juste Belmont is the first of his family who's programmed to control smoothly - in fact, just as he resembles Alucard, he moves and operates much like him as well, albeit with the Vampire Killer whip. As usual, 'A' makes Juste jump, 'B' makes him attack, 'Up' plus 'B' activates a sub-weapon, 'Start' opens the pause menu, and 'Select' opens the map. In this case, 'L' and 'R' make him dash left and right, respectively - no matter the direction he's facing - so he can get close to enemies and crack his whip at them and evade their attacks swiftly. Returning sub-weapons include: the Dagger, Holy Water, Boomerang, Axe, and Holy Book; new to this title is the Sacred Fist, which has Juste unleash a flurry of punches directly in front of him. The magic system herein operates on a less-is-more philosophy, Spell Fusion simply creating spells that activate when the 'Up' plus 'B' sub-weapon command is activated. The Spellbooks are the Fire, Ice, Bolt, and Wind Books, which cast elemental spells based on whichever sub-weapon is equipped, as well as the Summoning Tome, which summons a different monster for each sub-weapon equipped. It's not nearly as deep as the other Game Boy Advance Castlevania systems, though it does its job well and didn't distract KCET from the gameplay.
The RPG elements from Symphony of the Night and Circle of the Moon are present here as well. STR or Strength affects how much damage enemies take; DEF or Defense affects how much damage Juste takes; INT or Intelligence affects MP recovery rate; and LCK or Luck affects drop rate of rare items. Enemies that Juste meets throughout the game give less and less Experience as he goes up in level, 50 being around the highest he can get without grinding ridiculously against 1 EXP-yielding monsters. Simon's grandson can't equip alternate weapons to the Vampire Killer, but he can collect different kinds of "tips" that he can equip one at a time onto the end to give an extra effect. He can also equip armor to his Body and to his 3 Goods outlets, though the accessories equipped to the latter give better or worse stat alterations depending on which opening they're equipped to. 12 Relics will be collected, too, 3 of them adding extra abilities to Juste's moveset (the Slide, Double Jump, and High Jump), 3 of them allowing display of enemy names and damage, and 6 being Dracula's parts, these giving stat boosts and allowing Juste access to the final fight with Vlad himself. The odd Merchant will supply Juste with whatever he needs that he isn't able to collect in the game itself, including armor, accessories, and other items such as Potions and Castle Maps.
As the player will discover mid-way through the game, there are two layers to the castle which are identical structurally but contain different enemies, different aesthetics, and occasionally different objects to interact with. Exploring each map and filling in the blank spots is satisfying and addictive, and there's enough variety between each castle that it feels like a much better execution than Symphony of the Night's Inverted Castle was. Exploring as much as possible is rewarded, too, as much of the progression and advancement is achieved by way of specific castle interactions and with items found in little nooks just as much as it is by defeating bosses and gaining new abilities. There's even a room in the castle which is empty to begin with, Juste decorating it with furniture and art as he collects these; this is a quirky if unnecessary distraction.
Unlike in Circle of the Moon, once the game is beaten there are a couple rather interesting alternate modes to enjoy. The first is Maxim Mode, in which the player can play as Maxim Kischine in true free-roaming style, leveling up and exploring the entire castle with no strings attached - be it plot or the need for upgrades to his abilities. His control scheme is the same as Juste's, but he uses the Stellar Sword as his main weapon, is much faster, Triple Jumps instead of High Jumping, can perform a Screw Attack-esque roll at the end of a Triple Jumps, exclusively uses a Shuriken sub-weapon which he sends out and eventually returns to him - much like the Cross but moving in a circular motion and always coming back to Maxim, and has a couple exclusive spells. This is very much like Richter Mode in Symphony of the Night, and playing as Maxim is much more satisfying than playing as the main character with alternate stats as in Castlevania's GBA debut.
Besides this there's Boss Rush Mode, which has become a must for every Castleroid since. Depending on the difficulty level - Easy, Normal, and Hard being the options - Juste will fight the game's first five bosses, the first ten, or all of them one after another save for Maxim. At the beginning of the massacre Juste will be able to pick his sub-weapon of choice from a series of candles, and in-between each individual bloodbath thereafter he'll be able to replenish his hearts in an identical room with candles. This mode is a speed runner's dream come true, as the game itself counts and makes a record of the time taken to complete the whole course. Also, Maxim and the 1986 NES Simon Belmont can be taken through the mode, the latter by using the famous Konami Code while said company's logo is displayed. There's no in-game reward for beating this mode with a particular time, but conquering it with three decidedly different vampire hunters itself is reward enough - and giving the player useful items for making good time would be implemented in future Castlevanias featuring this mode.
Graphically, the series' second Game Boy Advance outing is as much of a looker as one could ask for on the system. Juste's sprite is stiff while standing still, carries an annoying trail of bright blue behind him as he moves, and has an ugly design overall, but it animates walking rather elegantly. Enemies are pretty and colorful, yet still intimidating - some taking up the entire screen's height. Though many are returning, there are plenty of well-made enemies all-new to the game. The environments are not only detailed, but quite varied - even between two castle versions of the same area. Harmony is much the graphical superior of Circle of the Moon, though some will prefer the latter's appearance for its dark and brooding nature.
Michiru Yamane, the composer responsible for the scores to Castlevania: Bloodlines and Symphony of the Night, returns for the music to this game. The compositions are truly brilliant, but suffer from a terrible chiptune-like quality - something that works for catchy old-school tunes, not sweeping arrangements along Symphony of the Night's lines. Both the amazing and less pleasant tracks leave the player wondering how they would have sounded in better quality. Still, when they shine they shine, and several are notable examples: 'Name Entry' is simply cool; 'Theme of Juste Belmont' has a beginning similar to 'Theme of Simon' before taking its own fast-paced route; 'Theme of Dracula' has the feel of impending evil; 'Last Battle' is chaotic and heroic at once; and the remix of 'Vampire Killer' that plays while playing as Simon Belmont in Boss Rush Mode is as fantastic a variation on the tune as had been done prior.
Despite having the simplest magic system of the 3 Game Boy Advance Castlevanias - Spell Fusion not nearly as massive as Circle of the Moon's DSS or Aria of Sorrow's Tactical Souls - Harmony of Dissonance is appealing for its creepy atmosphere, compelling dual castle, and for overall being an intensely fun Metroidvania. Different gamers generally have their own favorite when it comes to these uniquely appealing games, but as usual the middle child often receives less attention, despite its great - though inhibited - music, its bright yet eerie graphics, the compelling castle maps that are so addicting to fill in, the incredible Boss Rush Mode, and the amount of depth that is there - which is more than substantial. In this game, there truly is something so harmonious about the chaos of Castle Dracula.