This 2001 Action RPG adventure casts you as Nathan Graves, a vampire hunter exploring Dracula's sprawling, non-linear castle in 1830. Gameplay focuses on exploration, where finding artifacts unlocks new areas, combined with RPG elements like equipping armor to change stats. Its unique feature is the Dual Set-up System (DSS), allowing you to combine two cards to create unique magic spells, such as fire-whips or summoned demons. This title blends platforming and deep character customization.
This game adopts the exploration-focused structure popularized by later entries in the series. Dracula's castle is presented as one continuous, labyrinthine structure. Progression is gated not by reaching the end of a stage, but by discovering specific artifacts and gaining new abilities that unlock previously inaccessible areas. This encourages thorough backtracking and environmental puzzle-solving as players uncover the castle's secrets.
While the primary method of attack remains the traditional whip, character customization is central to the experience. Players can equip various types of armor and accessories, which directly influence Nathan's statistics. This RPG element allows for tailoring the hunter's capabilities to suit different challenges encountered within the castle.
The most distinctive mechanic in this installment is the Dual Set-up System, or DSS. This system involves combining two collectible cards—one "Magic Card" and one "Attribute Card"—to generate unique magical abilities and enhancements. The resulting combination dictates the effect:
This system offers a vast array of potential spells and powers, encouraging experimentation to find optimal combinations for different enemy types and exploration needs.
This title is classified as a Main Game, blending Platforming, Role-playing (RPG), and Adventure genres. It was originally released in 2001 and is currently available on the Game Boy Advance and the Wii U platform.
There are currently no officially released downloadable content packs or expansions associated with this game.

A port of Castlevania: Circle of the Moon included in "Castlevania Advance Collection." In Circle of the Moon, you can combine action and attribute cards to create over 80 unique spell effects, ranging from fire whips to ice blizzards, with the "Dual Set-up System." New Quality-of-Life features for this port are included, such as Rewind, Quick Save, and Record/Replay. The new Encyclopedia feature offers helpful information that helps you keep track of items, equipment, enemies, and the Dual Set-up System. With the new DSS Gadget option, you can get on-screen pop-ups that display the DSS Attribute & Action cards that are obtainable from the monsters you encounter in battle. The story follows Nathan Graves, a vampire hunter apprentice who enters Dracula's Castle along with his Master in order to prevent the dreaded return of the Count.

Circle of the Moon was a great Castlevania game, but the card system left something to be desired. Cards being dropped solely from enemies was less than desirable, since it meant that the main gimmick of the game was locked behind a game of dice. This mod makes the cards more accessible by placing them in specific locations around the world. Enemies who did drop cards now instead drop meat, as a nod to the classic style Castlevanias. Cards are generally placed in an ascending order of power; you won’t get big bone powers by searching the early areas.