Pokémon Platinum is the third game of Generation IV, after Pokémon Diamond and Pearl Versions. The version mascot is Giratina, which appears in its Origin Forme. The game was officially announced by Nintendo on May 15, 2008. The Japanese version was released on September 13, 2008. The game was released in the U.S. on March 22, 2009.
- The Wi-Fi area has been enhanced with the new Wi-Fi Plaza, which supports up to 20 people at once. The new area seems to focus exclusively on mini-games, which include Wobbuffet Pop, where players hit a Wobbuffet, and Merry Mime Jr., where players can balance Mime Jr. on a ball, Swallot Pop, where the player throws berries into the Swallot's mouth.
- There is a new key item called the Vs. Recorder (given to the player by Looker when the player first meets him in Jubilife City), which allows players to record battles in the Battle Frontier and Wi-Fi, and share the records with other players over the GTS. Battle records can be rated by other players when viewed, and the most popular battle records are displayed for all to see. Players can also take snapshots of their PC boxes and share them with other players in a similar fashion.
- New characters, international police Looker (codename), and Team Galactic Commander Charon appeared in Pokémon Platinum.
- The GTS has now incorporated an e-mail system that allows players to be notified of completed trades. Notification messages are sent to the player's actual e-mail address.
- The Sinnoh starters and their evolutions are now allowed in a newly-expanded Amity Square, allowing a total of 20 Pokémon to enter the park.
- Over local wireless, there is a new feature where the player and their friends can put their Pokémon Eggs in and randomly swap.
- HM05 (Defog) is now located on the bottom floor of the Solaceon Ruins, instead of Pastoria's Great Marsh.
- HM04 (Strength) is now obtained from Riley on Iron Island, instead of in the Lost Tower.
- On certain days of the week, there are Trainers that the player can challenge in certain Pokémon Centers, who are located in front of the Center's desk. This replaces the trainers that appear in Jubilife TV Station in Diamond & Pearl.
- The player meets Professor Rowan and the opposite gender character earlier, and obtains their Starter Pokémon on Route 201.
- The very first battle is against the player's rival who following tradition, has chosen the starter Pokémon with an advantage against the player's starter.
- The player and the rival now encounter Cyrus at Lake Verity at the beginning of the game. The player will also meet Cyrus at different areas, such as the Eterna City statue instead of first meeting him in Mt. Coronet.
- A double battle with the player's rival against Flint and Volkner occurs at the entrance to the Battle Frontier.
- Dawn/Lucas no longer gives the player the Dowsing Machine or the VS Seeker near the Route 206 junction. Instead, she/he now meets the player at the entrance to Mt. Coronet.
- Some of Sinnoh's Gym Leaders have been reordered. Fantina is now the third Gym Leader, Maylene is the fourth and Crasher Wake is now the fifth.
- Team Galactic's plans for world domination and the layouts of their HQs, such as their hideout in Eterna, have been changed. In addition, they openly recognize their goal, and are more villainous.
- The player is now able to challenge all the Gym Leaders of Sinnoh to rematches, as well as the player's tag battle partners from throughout the game (Cheryl, Buck, Marley, Mira, and Riley) can also be challenged in a restaurant located in the Survival Area, known as the Trainer Café. Each opponent has a team of five Pokémon, with levels between 65 and 78.
- The Elite Four's Pokémon are stronger after the player visits the Battle Zone, with levels between 65 and 78.
- Team Galactic gains control of Stark Mountain under the command of Charon; it is up to the player, with help from Buck, to defeat them.
- The Pokétch now allows Players to scroll up and down between applications instead of having to cycle through them all to reach a previous one.
- Some moves have been redesigned with a different animation, like Razor Leaf.
- When battling against certain Trainers, such as Gym Leaders and the rival, their sprites are now animated to move in the same manner as a Pokémon's sprite.
- Some Trainers use Seals when sending out their Pokémon.
- Three of the Gyms have been reordered. You can battle the Hearthome Gym the first visit to Hearthome, the Veilstone Gym is now the 4th gym and the Pastoria Gym is the 5th. The HMs allowed to be used after getting the Hearthome Badge and the Pastoria badge have changed to being HM05 Defog for the Relic Badge and HM03 Surf for the Fen Badge.
- Three of the region's Gyms have been changed. Eterna, Hearthome, and Veilstone Gyms have all been redesigned.
- Gym Leader closeups, just before a Gym battle, have been changed from enlarged sprites to higher-quality drawings, and the term VS.
- The template in battle for a Pokémon's name, level, and HP is now a dark gray instead of white, and its shape has also been changed.
- When entering new areas, the location labels in the top-left corner of the screen have been redesigned, similar to their update between Pokémon Ruby & Sapphire and Pokémon Emerald.
- When first visiting the Resort Area, the player is given access to a villa. Inside on a table, there is a catalog that lists different items that can be mail-ordered to decorate the house. This is similar to the Secret Bases of Hoenn.
- A new Battle Frontier takes the place of the Battle Park. The Battle Tower has been improved, the Battle Factory has returned. There are also 3 new attractions. The Battle Castle, Battle Roulette (Battle Arcade in the US), and Battle Stage (Battle Hall in the US).
- Patches of snow are scattered throughout Twinleaf Town and its nearby routes.
- Jubilife City has been refurbished with new pathways and some buildings have animated roof lights.
- Jubilife's Global Trade Station has been redesigned and is now called the Global Terminal.
- Two archways are around the entrances to Floaroma Town.
- Trees now cast very noticeable shadows in Eterna Forest. Some people think it is fog, but that is a common misconception.
- Cycling Road has been updated and now has dual tunnels in the middle of the route.
- Hearthome City has been updated with new pathways.
- Amity Square has been completely remodeled. It now includes a small lake, more paths, and more upper levels. The old buildings now contain warp panels which transport the player to other old buildings within Amity Square. In the center there is now an area with a mini Sinnoh theme.
- Lost Tower has a new color scheme, and now has fog on three of its five floors, which can be cleared with HM05 Defog.
- Solaceon Town's houses have been remodeled, and the Pokémon Daycare now has a trough filled with water and tent-like shelters.
- Veilstone City now has new pathways. Team Galactic's Veilstone HQ has been redesigned, inside and out. There is now a basement in the Veilstone Departmant Store that sells contest items.
- The Hotel Grand Lake has been updated with new pathways.
- Pastoria City's houses have been remodeled and now also includes a board with a Croagunk on it which is located in front of the Great Marsh.
- Pastoria's Great Marsh has a new color scheme, and also has foliage changed and added.
- Celestic Town's houses have been remodeled.
- Canalave City has new pathways, and its houses and library have also been remodeled.
- The player now needs to use HM08 (Rock Climb) to access Lake Acuity.
- The area of water south of Snowpoint City where the player boards the boat to the Battle Zone now contains small icebergs. These can also be seen in the ocean when the boat is crossing to the Battle Zone. The boat has also been redesigned, most likely due to the icebergs in the sea.
- Sunyshore City has been refurbished with new pathways, and its houses have been remodeled.
- The entrance to Victory Road is now five tiles wide, with a Poké Ball on the top of the entrance.
- Sinnoh's climate has changed drastically. Snow is now found as far south as Twinleaf Town, whereas the Battle Zone is more tropical, now with palm trees.
- Stark Mountain now represents a volcano, showing real lava and has numerous crags.
Elite Four and Champion
- Pokémon Platinum can connect automatically to Pokémon Diamond and Pokémon Pearl once the player has access to a Pokémon Center. This game, however, is unable to connect with My Pokémon Ranch, but is able to connect to Pokémon Battle Revolution and to Generation III games. It is known that Nintendo planned to release a patch that will allow My Pokémon Ranch to be compatible.