Castlevania: Harmony of Dissonance is a platform-adventure video game developed by Konami Computer Entertainment Tokyo and published by Konami for the Game Boy Advance. Part of Konami's Castlevania video game series, it is the second installment of the series on the Game Boy Advance. It was released in Japan in June 2002, in North America in September 2002, and in Europe in October 2002. Harmony of Dissonance occurs in the fictional universe of the Castlevania series; the premise of the series centers on the eternal conflict between the vampire hunters of the Belmont clan and the immortal vampire Dracula. Set fifty years after Simon Belmont vanquished Dracula's curse, Harmony of Dissonance focuses on his grandson Juste Belmont and his quest to rescue a kidnapped childhood friend. Koji Igarashi produced Harmony of Dissonance with the intent of "creat[ing] a game that was similar to Castlevania: Symphony of the Night", the critically acclaimed PlayStation game that he had worked on. Harmony of Dissonance sold 126,000 units in the United States in its first three months of sales, but it was not a success in Japan. Critics praised its graphics which was considered an improvement over its predecessor, gameplay, and return to elements from Symphony of the Night, while criticism was directed towards its confusing progression, story, and music. The game was re-released as part of the Castlevania Advance Collection on September 23, 2021 for the Nintendo Switch, PlayStation 4, Xbox One and Windows alongside Castlevania: Circle of the Moon, Castlevania: Aria of Sorrow, and Castlevania: Dracula X. Gameplay Harmony of Dissonance makes use of a 2D side-scrolling style of gameplay, similar to many of the previous Castlevania video games. The objective of the game is to lead the player-character, Juste Belmont, through the monster-filled castle as he searches for his kidnapped friend. The castle consists of two "layers": Castle A and B. Structurally, each castle has mostly the same room layout, but monster types, items, and other aspects vary between the two versions. Later, the player can use special warp rooms that can teleport Juste to other castle rooms and between castles. The two castles share a connection; for example, the destruction of a wall in one castle can cause a change in the other. The game further divides the castle into various, named areas: the Shrine of the Apostates, for example. Relics and keys found within the castle allow Juste to