Storyline changes
The player meets Professor Rowan and the opposite gender character earlier, and obtains his or her starter Pokémon on Route 201.
The first battle is against the player's rival, who, as always, has chosen the starter Pokémon that weakens that of the player.
The player and the rival now encounter Cyrus at Lake Verity at the start of the game. The player can also meet Cyrus at different venues such as the Eterna City statue.
Both Dialga and Palkia appear on Spear Pillar. Giratina, the mascot of Platinum, then phases into the world in front of Cyrus.
A new area known as the Distortion World (Japanese: やぶれたせかい Torn World) is playable. It has floor-like sections floating at ninety-degree angles from each other, creating an effect similar to the art of M. C. Escher. It doesn't follow the Laws of Physics, making things like surfing down a waterfall going up possible. The camera angle switches between perspective and isometric views to suit the angle of the player. It also has moving platforms with jumpable gaps between them. Giratina, when here, will be in its Origin Forme and is also the only wild Pokémon located here.
At least two new characters were added. One is Pluto, a professor of Team Galactic, and the other is a police officer spying on Team Galactic, using the codename "Looker"
.
A tag battle between the player and his or her rival against Flint and Volkner takes place at the entrance to the Battle Frontier when the player first arrives there.
Team Galactic's plans for world domination and the layouts of their HQs, such as the one in Eterna, have been changed. In addition, they openly recognize their goal and are more openly villainous.
Some of the Gym Leaders have been reordered: Fantina is now the third Gym Leader, Maylene is the fourth and Crasher Wake is the fifth.
Dawn/Lucas no longer gives the player the Dowsing Machine or the Vs Seeker near the Route 206 junction; instead he/she meets the player at the entrance to Mt. Coronet.
Team Galactic appear in Stark Mountain under the command of Pluto, who seeks to use the destructive power of the volcano to extort money from the people of Sinnoh. The player, with help from Buck, must defeat them. During this event, Mars and Jupiter quit Team Galactic because Pluto does not share the same ideals as ex-boss Cyrus. Ultimately, Pluto and his two accompanying grunts are apprehended by Looker and two policemen.
After the aforementioned event, the player is able to challenge all the Gym Leaders of Sinnoh to rematches in the Match Place. The player's tag battle partners from throughout the game (Cheryl, Buck, Marley, Mira, and Riley) are also able to be challenged in this café. Each of the 13 characters has a team of five Pokémon, whose levels are between 61 and 66.
The Elite Four increase their Pokémon's levels after the player has completed the Stark Mountain event. Their levels are now between 65 and 78.
When one finishes the Stark Mountain quest, instead of the rival appearing at the Fight Area on weekends, he now appears at the Survival Area in front of the Match Place. During the first battle, the levels of the Pokémon in his party range from 59-65, second battle 69-75, and third and beyond 79-85. On his last battle, he is the trainer with the highest-leveled Pokémon in all main series games.
When first visiting the Resort Area, the player receives a villa. Inside on a table is a catalog that lists items that can be purchased to furnish the house in the same manner as decorating a secret base. The player will be visited by NPCs such as the Sinnoh Gym Leaders, the player's mom, Professor Rowan, and the rival.
So... Yea.