The Castlevania Advance Collection compiles all of the Castlevania games originally released on the Game Boy Advance and the Super Nintendo's Castlevania: Dracula X. Most of these games follow the excellent Metroid-style action-exploration formula introduced by Symphony of the Night, codifying the "Metroidvania" genre. Featuring a sprawling map filled with a large variety of enemies to defeat and items to collect, the addicting exploration formula and the encouragement of speed-running made the Castlevania series a perfect fit for Nintendo's portable console.
Much like Symphony of the Night, all of the games in the Advance Collection have many bonus modes and features that are accessed via the Entry Name screen, sometimes requiring the given game to be completed once. Entering a special name before starting a new game usually allows for a new playable character that dramatically changes how the game is played. Other times, these special names may unlock bonus features early.
Aria of Sorrow
Aria of Sorrow follows the tale of Soma Cruz, a transfer student to Japan who mysteriously receives the ability to command the monsters of Dracula's Castle at the dawn of a solar eclipse. The last and often considered the best of the Castlevania games on the Game Boy Advance, all of the unlockables in Aria of Sorrow will require the game to have been beaten once, where the Hard difficulty mode will become available to the player.
There are only three names to enter that will significantly change the game, with the first being "JULIUS." As it suggests, entering this name allows the player to play through the whole game again as Julius Belmont. The other two codes are purely for players looking for a challenge: "NOSOUL" and "NOUSE." "NOUSE" turns off the use of items for the entire playthrough, while "NOSOUL" turns off the use of Souls except for the essential Souls required for traversal, cutting Soma off from the vast majority of his powers.
Harmony of Dissonance
Harmony of Dissonance stars Juste Belmont, a descendant of the famous Simon Belmont who is thrust into the adventure after his childhood friend is kidnapped in a mysterious castle resembling Dracula's. Harmony continues the trend of using secret codes to use at the entry screen, though the changes aren't quite as diverse as in Aria of Sorrow. Only one of these three codes needs a completed playthrough to work, while the others can be used right off the bat.
Entering in "HARDGAME" unlocks Hard difficulty at the start of the game, while "NO MAGIC" disables Spell Books, preventing the use of extremely powerful Spell Fusions that make up much of Juste's moveset. "MAXIM" can only be entered after completing the game once, allowing the player to step into the shoes of Juste's friend Maxim Kischine.
Circle of the Moon
One of the underrated classics of the Game Boy Advance's launch lineup, Circle of the Moon is a non-canon adventure that follows distant Nathan Graves as he tries to save his father Hugh from the clutches of Dracula. Each code in Circle of the Moon unlocks a new mode that changes Nathan's starting stats, but each new code is only given after completing what was unlocked by the previous code.
"FIREBALL" unlocks Magician Mode, which has Nathan start with all DSS cards and high magic stats at the cost of other stats. "GRADIUS" unlocks Fighter Mode, significantly increasing Nathan's strength and defense, but other stats are weaker. "CROSSBOW" unlocks Shooter Mode, which increases his sub-weapons' strength while weakening his other stats. Finally, "DAGGER" unlocks Thief Mode, the hardest mode of all that only increases Luck, badly lowering all other stats.
Dracula X
This Super Nintendo re-imagining of the acclaimed Rondo of Blood is divisive since it had to cut a lot of corners and re-arrange a lot of things to fit on the cartridge, but the unique levels and SNES soundtrack earned it its share of fans. Still, Dracula X can be unfairly difficult even for a classic Castlevania title, so players may want to take advantage of the password system to get ahead of the game.
Much like Bloodlines and Super Castlevania IV, Dracula X has no Name Entry screen but rather a Mega Man-style icon password system. The differing combinations start Richter on a specific level with varying items depending on the icons used. While there are no special passwords that unlock a particularly cool mode or a new character, changing the bottom-right fire to an axe places Richter at the last stage with the conditions for the best ending already met.