Aria of Sorrow fixes all the problems that its predecessors had and ends up being one of the best in the series.
This entry in the series has you taking control of Soma Cruz. He's a transfer student who is studying abroad in Japan and the solar eclipse of 2035 is about to occur (yes, this Castlevania entry takes place in the future instead of the past). The Hakuba shrine where his childhood friend and only daughter of the shrine's caretaker, Mina Hakuba resides is where he decides to watch it. On his way up there though, he has a strange feeling and by the time he gets up there and the solar eclipse occurs, he goes unconscious and he awakens in a mysterious castle together with his friend. Now it's up to him (together with a few other people stuck in the castle) to find a way to get out of the castle and save their lives.
The plot has never been the central point of the 2D Castlevania games as the character development and dialogue is always rather weak. Usually, the story just serves as an excuse to go through Dracula's Castle and have some fun destroying enemies and exploring. Aria of Sorrow however takes things a bit further than "just an excuse" as it actually has some pretty interesting characters and the dialogue is written better than most of the other Castlevania games. For once, your main goal at the beginning is not to go and kill Dracula to save the world but simply to find a way to escape (like any other person would want to do). The story then gradually builds up from there with you being introduced to a cast of other characters who help explain the story even further. Even with all I've said, the storyline in this game isn't anything special but I appreciate the fact that Konami went through a lot more effort into producing a plot than they usually do with the other games in the series.
The aspect that the Castlevania series has always specialized however is its extremely fun and deep gameplay and Aria of Sorrow's gameplay is the best out of the Gameboy Advance entries so far. Soma is just like any other protagonist in the series that has appeared since Symphony of the Night in which he equips a variety of items like copper plates, pendants, rings, and suits in order to enhance his stats and stand a chance against the tougher enemies later on in the game. What definitely makes Soma different from the other heroes on the GBA Castlevanias is that he doesn't just wield a whip for the entire game. He can equip a variety of swords, axes, knives, spears, and even a handgun to take out his enemies (too bad there's only one pistol in this game and the damage it does is terrible). This definitely adds more depth to the game because not only will you be taking into consideration the damage that your weapon does to the enemy, but also the range, elemental attribute, and attack speed (it's no use if your weapons is strong but can't penetrate through the enemy's defenses).
Replacing the DDS Cards of Circle of the Moon and the Spell Books of Harmony of Dissonance, Aria of Sorrow also comes with a new gameplay feature known as soul collecting. Soma has a strange power in him which allows him to absorb the souls of the enemies he defeats. Equipping these souls allow you to perform special abilities, upgrade your stats, or give Soma some new offensive skills. If you ever wanted to be like an enemy and throw bones at your opponents like the skeletons do, shoot out razor sharp feathers like the harpies, or throw hand grenades like the zombie soldiers, then you'll absolutely love this feature. Like I pointed out earlier, you can also equip souls that raise your stats (strength, mind, intelligence, etc.) to increase Soma's efficiency in combat and also equip special abilities like transforming into a large monster which allows you to cut through paths at a great speed while taking out the monsters on the way. This new monster soul feature, together with the smoothened combat system which adds a lot of depth to this Castlevania makes this one of the strongest handheld Castlevania games yet in terms of gameplay.
Even if the gameplay is great, this game doesn't have that whole "I'll do well in this part but sacrifice some of my other qualities for it" ideal that Harmony of Dissonance had (which had improved graphics but terrible sound quality in comparison to Circle of the Moon) which means that it is extremely impressive from the technical standpoint. The graphics in this game are simply great. Soma animates much more fluidly than other Castlevania protagonists and controlling him feels extremely smooth and responsive. Enemies (the bosses in particular) are also animated extremely well and very detailed. Environments are also extremely atmospheric with nice added touches like bats flying in the background and crumbling debris inhabiting the background. It can be easily seen that a lot of effort went into the graphical design of this game and that it uses the Gameboy Advance's technology extremely well.
Like I explained earlier, Aria of Sorrow doesn't skimp out in the audio. The sound quality of the music in this game is spectacular with the music itself being quite notable, catchy, and very atmospheric which just adds to this game a lot in terms of why it's so good. There are also lots of voice clips in comparison to the earlier games on the system (unlike the later DS titles though, they're all in Japanese and haven't been localized into English) which shows that Konami is indeed putting in quite a bit of effort into this game. Sound effects are all very solid and all in all, I had little to no complaints about the audio in Aria of Sorrow.
Much like many handheld Castlevania games, this entry in the series doesn't last too long. It lasts a good 5-10 hours depending on how much you decide to explore the castle. While it may seem a bit short for those who spend hours on end playing games, it's a perfect length for those who like playing in short bursts. For those expecting a long sprawling epic adventure, you won't find it in Aria of Sorrow but for those who just want a fun action platformer then you'll find this game's length to be perfect.
In the end, Aria of Sorrow is the pinnacle of Castlevania games on the Gameboy Advance. The controls are far smoother than any of the handheld entries so far, the graphics make great use of the system's technology, and there's more effort put into the plot than usual. This game is definitely one of the most fun and enjoyable ones so far in the series and those looking for a great action platformer can't possibly go wrong with this game. Even if you didn't like the previous Gameboy Advance entries for whatever reason, be it the sound quality, somewhat stiff controls, or graphics, then I'd still say you should give Aria of Sorrow a chance because it improves upon almost everything. It definitely gets a high recommendation from me.