The player controls the protagonists of Stardust Crusaders in a combination of Point and click adventure and classic third-person RPG. It is sometimes also referred to as a side-scrolling RPG.
Just like in the story, the game features Jotaro Kujo and his companions traveling the world together and battling enemy Stand Users to reach DIO. Like most RPGs, the player manages the heroes of Stardust Crusaders who can level up as they fight and whose health (named HP) and mental state (named "mental points" or MP) must be taken care of. If either HP or MP reaches 0, then the character is down or is too discouraged to fight. The game's Biorhythm System (バイオリズムシステム,Baiorizumu Shisutemu) also modifies how well a character can fight depending on their state of mind such as stress. The characters can also buy, use or equip items.
The camera is positioned in front of the controlled character and only a horizontal stripe at the center of the screen is used to display the characters and the environment. The character can thus only really move left or right in a given screen and go from screen to screen only a key points that allow traveling upward. The bottom half of the screen is used to display the faces of the characters and gameplay options while the top half displays dialogs. Other menus allow looking at detailed stats of the characters.
The player can take the following actions when not in combat:
Use the cursor to examine and interact with points of interest in the environment, as well as uncover hidden items.
Interacts with other characters on-screen, such as shopkeepers or other NPCs. This can advance the story, provide useful hints on what to do next, or simply give bits of lore or flavor.
This opens another set of options: USE, EQUIP, REMOVE, or TRASH. The USE option opens the list of consumable items such as vitamins or cigarettes, and allows the player to use them. EQUIP prompts the player to select a character, and then select an item to be equipped by that character. REMOVE opens the equipped items page for a character and allows the player to remove any equipped items. TRASH allows the player to destroy any items permanently.
If the player has any tarot cards in their inventory, Avdol can perform a fortune-telling for any one character. He will mention the name of a "lucky" item for that character to equip. This will consume the tarot card.
Status Menu Bug
It is extremely easy to trigger a game-breaking bug. If, after opening the Status Menu (X button), any other button is pressed instead of closing out of the Menu (B button), the game will be stuck in the Status Menu. There is no way to close the menu at this point and the player must restart the game and load a previous save. This bug was present in the original Japanese cartridge of the game.
Prior to a battle, the player selects one of the face-down cards offered by DIO. These cards can either have beneficial effects on the party, such as restoring HP, or harmful effects, such as lowering defense.
The game uses a turn-based combat system. At the beginning of a turn, the player selects what actions each of the party's member must do and the turn unfolds. The enemy will usually attack the characters to reduce their HP, or "talk" at them to attempt to reduce their MP. A character's Stress level affects how susceptible they are to an enemy's demoralizing words; characters with lower Stress have a higher chance of resisting.
When a character's HP or MP reaches 0, that character will fall unconscious. However, that character can be revived in battle using an item such as a restorative.
The player characters can take the following actions during a combat encounter:
A standard attack to deal damage to the enemy target's HP. The higher the MP of a character, the stronger their attacks will be. The enemy can also dodge attacks.
The character says a line inspired by the manga. This can be used to taunt the enemy into damaging their MP, or encourage allies, restoring their MP
Consumable items can be used in combat, providing benefits such as restoring HP/MP or reviving fallen teammates.
The character passes their turn. This can unlock further actions: IDEA or GUTS.
These additional actions can be unlocked after CHECKing a turn:
GUTS - a stronger version of the standard attack that deals more damage.
IDEA - in certain situations, a character may get an idea of what to do and perform a special action to help the party defeat the enemy. These actions are situational to specific bosses and are inspired by the events of the manga. Oftentimes, a boss cannot be defeated without the player executing an idea.
The storyline used deviates somewhat from its source, likely due to system limitations.
"Dollars" are always used as currency, regardless of the country.
Members of the Speedwagon Foundation appear more frequently to provide clues and money for the heroes (if they sacrifice a day of their trip to rest).
Joseph routinely uses hisStand on TVs found throughout their journey in order to locate DIO. During these scenes, DIO can see and talk with the entire party. In the original story, he is only seen doing this once.
Vampires and zombies randomly attack the team in "dungeons" (they were originally scarce in Part 3). The few instances of Joseph's Ripple are absent from the game.
Polnareff first appears as a shop-clerk in a Japanese bookstore. Joseph suggests going there to find a book about DIO and Stands; in the original story, this information is passed through word of mouth by Stand users.
Forever's Stand Strength takes the form of a mansion instead of a boat, and is also in Japan; the fight takes place before Jotaro and allies even depart.
Dark Blue Moon attacks the party within a water trap inside a sewer route found in the mansion.
Midler is a stewardess on the same plane, and her Stand takes on the shape of the restroom's doorknob instead of a mug of coffee in the would-be submarine.
Steely Dan doesn't appear, though he is mentioned in the instruction manual. The Lovers, subsequently, isn't his Stand, but some sort of seed.
Enya the Hag is responsible for putting The Lovers into Joseph's head. Due to Steely Dan's removal from the game, Star Platinum and Magician's Red enter Joseph's brain along with Hierophant Green and Silver Chariot (in the original manga, it is only Hierophant Green and Silver Chariot who enter).
Oingo and Boingo are reduced to a supporting role and do not use their respective Stands.
Iggy appears at a pyramid in the desert. The part with Geb was almost entirely removed.
Alessi transforms Kakyoin, Joseph, and Avdol into children (in the original manga, he only transforms Jotaro and Polnareff). He also attacks them within a library, being supported by the Oingo Boingo brothers.
Jotaro's group obtain Anubis' sword from a strongbox in a pyramid. Khan is a merchant rather than a barber and negotiates with them to buy the sword. When they refuse, he steals it.
Chaka is a weapons dealer. He asks to take a look at the Anubis sword and is subsequently manipulated by it into attacking. Anubis is only used twice, but still maintains the same level of power.
Chaka and Khan's order of appearance is also reversed (in relation to the original manga).
Daniel J. D'Arby still plays cards but wins by playing normally. His entire scene is scripted as well; In order of Polnareff, Kakyoin, Avdol, Joseph, and Jotaro, the group plays him, losing without fail until it is Jotaro's turn, wherein he will win automatically.
Telence T. D'Arby battles normally as if his Stand was a power type (instead of betting and playing minigames).
Vanilla Ice is beaten normally (rather than being destroyed due to sunlight).
Nukesaku doesn't appear; DIO is already waiting for the main party.
Jotaro gains the ability to move through stopped time only after he wears a special school uniform for it found in DIO's mansion (in the original manga, he does this naturally).
Kakyoin, Avdol, and Iggy do not die and instead survive with the rest of the group at the end.