Poor
Harmony of Dissonance is one of the most poorly designed and produced game in the Castlevania series.

There is a lot of backtracking and dead-ends, because the castle is designed very unfriendly (for beginers it can be even unplayable).

Item and spell system is not fun at all: the whip works almost the same way all the time and there is no need to use any other spell except one good (eg. Holy Book + Thunder).

If you would like to play Castlevania on GBA, then I suggest buying Great Circle of the Moon (if you prefer wonderful classic Castlevania gameplay) or Aria of Sorrow (if you prefer really well done changes to the classic gameplay).