From what I had read, Castlevania: Harmony of Dissonance was the lesser of GBA Castlevania games. So when I picked up the Castlevania Double Pack I wasn't expecting much. Having now played through the game I was pleasantly surprised.
While the previous Circle of the Moon seemed like a good game at the time, once I played Harmony I realized that Circle was missing much of the baroque/gothic style established in the PSX Symphony of the Night. In fact, this game is pretty much a spiritual successor to Symphony, albeit toned down.
Graphics are more varied with elaborate animations and special effects. The running animation is a little stilted though. Designed for the pre-backlit Gameboy Advance, the graphics can be on the bright side, appearing washed out or with too much contrast. Otherwise the graphics are great.
The music is decidedly low-fi during gameplay, as the Gameboy Color sound chip is used. Many of the songs are quite good, but some can be a little grating. The control is pretty much spot on and game length is decent for a portable game (I put in about ten hours.)
The story start similarly to Circle of the Moon, featuring two friendly rival vampire hunters. It ties in nicely with Castlevania II: Simon's Quest and has a twist on the reason for the arrival of Dracula's castle. As a Belmont, the chain whip from Super Castlevania IV is back. You can also use magic—adding spell attributes to secondary weapons as well as your whip.
Playing off the idea of two castles established in Symphony of the Night, the castle is initially a mystery to explore. Figuring out different puzzles and how to navigate the castle is both fun and a little frustrating and obtuse. It also involves an excessive amount of backtracking during one section. The game is a little too easy, especially during the boss fights.
The extra Boss Rush mode—with the option to play as the original NES Simon Belmont in all his three color pixelated glory—is a nice touch.
Overall this is a solid Castlevania with some interesting variations on the formula established by Symphony of the Night. While the game is easy and a little uneven in many areas, the castle is more fun to explore than the one in Circle of the Moon, and the game held my interest until the end.