Graphics: 8 Really amazing graphics for the GBA, especially given how early it came out. But, the horror stories are true about not being able to see it without backlighting. If you own an SP, the dark backgrounds will not be a problem for you at all. Excellent animation and 3D graphics for some parts. No slow down even when lots is going on, which can happen often.
Gameplay: 10 Following the tradition of Symphony of the Night on PS1, Circle of the Moon harkens back to the old Castlevania days when it was more about gameplay than graphics. Addictive RPG Action style gameplay will have you searching the entire castle (which is quite large) for every powerup and enemy you can find.
Sound: 9 Great music and even better sound effects.
Replay: 10 Lots to do and even more to do once you've beaten the game (with cheat codes). Lots of levels of difficulty (using cheat codes).
Overall: 10 You must own this game. Especially if you have the backlit SPs. Amazing adventure game that no one should go without.