Pokémon Ruby/Sapphire/Emerald Co-op Mode

By the use of a game-altering device, the capabilities and limitations of a 'co-op' mode in Generation III can be shown when forced outside of the Colosseum, Union Room or Records Room. In theory, this way it is possible to explore Hoenn with a friend with up to four players.

Example method (Ruby/Sapphire)

At least one game-altering device is required for this method, the player needs to temporarily change the game's coding to allow the player to walk through walls, preferably by the Gameshark code CE2CCCB25D8D815D. (NTSC/US version)

1. The code can be activated as soon as the game starts up.

2. In a Pokémon Center, travel one step above the woman at the Record Room counter.

3. Save the game. If only one cheating device is owned, the player should save the game and pass the cheating device to another person; Step One and Step Two should be repeated until all people are above the woman at the counter.

4. Start up the link like normal.

5. Instead of going to the room, since the player always travels at the same path (relative to his or her location), he/she will walk one step above the door and the game will not crash but rather take both players elsewhere to a valid area, due to the structure of the game's RAM. Regardless of both players not being in the Records Room, the communication between both players is not lost.

6. Both players are now free to explore Hoenn.

Example method (Emerald)

Since the game engine for Pokémon Emerald is different, the game will send the player to the Records Room, rather than Petalburg City. However, this problem can be ammended by redefining the next location the player arrives in by using a 'warp code'. Unlike the example shown for Pokémon Ruby and Sapphire, a 'walk through walls' cheat is not required.

1. Activate any warp code, preferably one which can be enabled by pressing a button, such as the Gameshark code 9D888122 8CFB57D8 734D21AC ABA1D48F (NTSC/US) which will take the player to Petalburg City when the next time he or she travels through a door after holding the R button.

2. Start up the link like normal. When walking through the door, if the code requires the player to hold a button, he or she should hold down the relevant button, depending on the code.

3. The player should appear in the 'warp location', rather than the record room.

Limitations of the game engine

Through experimentation, it has been found that if one player enters another location when communicated to another player, when entering a new location, the background will fail to load correctly. The graphics can be restored however, by simply changing the game to activate another valid interface such as the Pokénav as when closed the game will always reload the graphics. Regardless of this, the collision detections will always still be slightly off, presumably because of the fact that simultaneously the other player would be in a different section of the game map.

Trainer Battles can be fought when both players are linked this way but one should always speak to the trainer, which may suggest that the bytes managing the "!" mark appearing and the trainer walking up to the player are disabled when both players link up. These battles however, often end with the game freezing. As the menu was changed to how it should be in the relevant communcation room, the Bag cannot be opened, hence items and HMs cannot be used. It has also been found that doors cannot be entered when both players are in communication with each other, possibly suggesting that another pointer is used for when the player steps out of a door instead, maybe to support the capabilities of a text box being displayed; as the only valid warp in this case would be the exit to the relevant communication room which would ask one of the players whether he or she wants to leave. Interestingly, when a player is in communication with another, for unknown reasons he or she the player gains the ability to walk on water, even if a game-altering device was not used to allow the player to do so.

The games are not completely synchronized however, interestingly there are no limitations to the movement of NPCs which can suggest that the game does not make movement completely free to the other players, but rather every other NPC on the current map instead. This can cause some games to have a player walking into someone, while in another they are farther away. This can be fixed by trying to move the players so that they are the same on each screen, but this is never perfect.

In the case that one player has progressed in the game further than another player, for example in early gameplay when a man stops to take the player to Petalburg City; if this event has been 'cleared' in the other game, the game that hasn't been cleared will show the character from the other game stop at the barrier, and that player will be locked in place for that game. This will make synchronization impossible, unless the games are reset.

External Links

1. [1] - How to perform (Youtube).