The first two types of souls require some of Soma's magic points as he uses their respective abilities, but magic points can readily be restored by collecting hearts that appear when you break objects in the environment. Between all the different weapons and souls you can find, there's really a lot you can do to change the way Soma acts in battle. It can be fun to try to think of powerful, new combinations of weapons and souls, especially if you're trying to come up with the best way to defeat one of the game's tough boss monsters.
The Castlevania formula is well worn by now, but Aria of Sorrow is about as fun as these games have ever been.
Besides his weapons and soul-stealing abilities, Soma has the standard Castlevania hero abilities to run and jump, but sure enough he gains additional powers that soon allow him to double-jump, slide-tackle, and even fly. With all those different powers at your disposal, you might be a bit disappointed to find that Dracula's castle is actually pretty straightforward and doesn't give you too much opportunity to really get the most out of all this stuff. Aria of Sorrow isn't a very long game, weighing in at about 10 hours until the final confrontation, and most of the environments are just long hallways filled with monsters. You'll hit the occasional dead end in the form of a chasm that's too wide for you to jump across, or something to that effect, and will later return with new powers that allow you to get to the other side. Sometimes it can be difficult to remember where you're supposed to go next. You have convenient access to a map of all the regions you've explored, but it doesn't do much to tell you where to go next. So you'll wander around until you figure it out. Soma gains experience levels as he defeats enemies and eventually becomes practically unstoppable, so there's little challenge in backtracking through the castle.
Castlevania: Aria of Sorrow is more polished than the previous two Castlevania games. Fans of those games will notice that simple actions like saving your progress, checking the map, and accessing your inventory are faster than in the previous games, which helps keep the pace nice and quick. The soul-stealing system is simple in practice yet has plenty of depth, and the quality of the game's graphics and sound are both great. Soma animates smoothly, and most all the enemies look very good, especially the game's huge bosses. Some of the graphics are obviously recycled from previous games, but everything looks sharp and colorful, and the game makes use of some impressive visual effects to boot. The music, though mostly forgettable, definitely sounds better than that of last year's game, and the weapons and enemies all make realistic noises that add to the game's atmosphere.
There's a ton of variety and some good replay value to make Aria well worth picking up.
Aria of Sorrow features a "sleep mode," which is actually mislabeled, since it's more of a quick save--you can use it to instantly save your progress at any point, in case you immediately need to stop playing. When your resume your progress, the quick save is deleted, to keep you honest. And this is the first Castlevania with a link-up mode, by means of which you and a friend can trade the souls you've collected in an effort to complete your collections. Too bad Konami didn't go a step further and allow you and a friend to duke it out in an arena deathmatch, using your personal combinations of weapons and souls. A cooperative mode would have been great, too. Not that the game is lacking in replayability. There are several different endings, plus a hidden playable character that controls a lot like Harmony's Juste.
Though it may have room for improvement and innovation, the Castlevania series is nevertheless in top form with Aria of Sorrow. This is just a really great action game in the same vein as classics like Symphony of the Night and Super Metroid before it, and it stands tall among the GBA's best action games, including Circle of the Moon and last year's Metroid Fusion. Castlevania fans owe it to themselves to give Aria a shot, and anyone who might have missed out on either or both previous GBA Castlevanias would more than likely enjoy it as well.