Anyone who loves action/platformers should invest in this game, it is worthy of the Castlevania name.
Circle of the Moon has you playing as Nathan Graves and you are seperated from your partners after an encounter with Dracula. Dracula has been brought to life by Camilla, and then after the encounter you fall through a hole and your compainion Morris is captured. You start the game equipped with the classic whip as you maneuver through the underground. It is actually more like a past Metroid, as in takes place in the past because the style of gameplay and map system and level layout is very similar to Metroid. Circle of the Moon doesn't really direct you in any directions, like in Metroid so you can basically go any route that seems fitting until you have reached the end destination. Of course, you can't just rush there because there are boss fights, mini boss fights and items to collect and believe me, you don't want to stay the starting speed the whole game through. You'll collect some really neat weapons and items including many very familiar ones that fans of past Castlevania games will take notice and enjoy. You also level up in the game and improve your HP and MP.
The wandering around, picking your own destination aspect of this game works nicely because it makes it as un-linear as possible. You may get lost though because the area is so huge and there is so much to explore. It's a rather long game as well, at least for a GBA game, it should take you around 5-10 hours to beat but there are always places to explore, and just like in Metroid games, you'll have the urge to replay. Even after you've beaten it, this game is absolutely perfect for long, boring car trips because it never really gets boring to the point of putting it down for good. It may not sound like a long game but it is also on the challenging side so if your gamer skill level isn't very high than you expect to spend some more time with it as long as you don't give up. You'll even find some neat unlockables, but why spoil the surprise for you? See them for yourself when you purchase Circle of the Moon.
The new R and L buttons which weren't on the Gameboy Color are put to use with this game. Making it more controllable. L button is used for most magic and R button for some cool special attacks. They bring some light to an already brilliant game. One thing, however, I did not like about Circle of the Moon is the speed of Nathan. He walks to slow and if you want him to dash, you have to get a power up (Which is actually very early in the game) where you double tap the direction to dash. I wished I wouldn't have to double tap, it would've made it a little easier. Nathan does, though, have superior jumping skills and you'll learn more jumping skills as you progress through the game.
Now the music of this game was amazing. You'll hear some of the best songs in a handheld game period. Even though it came out five years ago, it sounds much better than a lot of recent GBA games from this year. The sound effects are also really well done because you can even hear small touches such as Nathan's feet hitting the ground after he lands from a jump. The sound was very well done, and the music even more so. The visuals, now probably look dated to anyone holding a DS in the palms of their hands, but for a launch title GBA game, this looked breathtaking. It features amazingly, detailed environments and an amazing art style that we all know from past 2D entries in the Castlevania series. The detail is very good. One little touch may be that a little more detail in the character models would be nice but I think this game outdid itself for the expectations of the visuals in a Gameboy Advance game. It definitely surprised me playing it for the first time, five years after release.
All in all, Castlevania: Circle of the Moon is a definite addition to anyone with a Gameboy Advance, Gameboy Player, or Nintendo DS. Anyone who likes action platformers should find a lot to like with this superb title.