Sonic Party 9 is the ninth home console installment of the Sonic Party series and the second and final installment for the Wii. The game was the first in the series to be developed by Nd Cube instead of Hudson Soft. It is also the eleventh in the main series (fifteenth in Japan). The host of the game is Chao for the boards while Hero Chao is the host for minigames, and Dark Chao appears near the end of Boards to initiate an event similar to the Last Five Turns Event from past Sonic Party games. This is also the twenty-fifth and the final installment of the Sonic franchise overall to be released for the Wii console. Unlike Sonic Party 8, the game features widescreen support.
On a night outside of Princess Sally Acorn's Kingdom, Sonic and his friends are gathered to watch the Mini Chaos Emeradls glitter in the sky. As Sonic peers though the telescope, he is shocked as he notices that the stars are suddenly being sucked through a vortex. It is then revealed to be Dr. Eggman and Metal Sonic. on a spacecraft, who are using a vacuum-like machine to suck the stars out of the sky and into containers. Upon witnessing this, Mario and the gang set out to defeat them and save the Mini Chaos Emeralds. After they start their journey, Hero Chao and Dark Chao are seen coming out of the woods and start following them, as part of Dr. Eggman's plan.
Before each board, there is a cutscene that features Dr. Eggman admiring his collection of Mini Chaos Emeralds. Metal Sonic then runs over to him to show his boss the progression of Sonic's group. Dr. Eggman is enraged, but summons two of his minions to stop the group before they can take all the Mini Stars. Eventually, however, the group reaches Dr. Eggman's location, Dr. Eggman Station, and must face Metal Sonic before battling his boss.
After the final battle with Dr. Eggman, the player looks out from the stadium at Dr. Eggman's other platform, where the canisters containing all the Mini Chaos Emeralds burst and release them back to where they once were. As this happens, Dr. Eggman and Metal Sonic are flying off. Dr. Eggman is mourning over the failure of his plan, which he reveals was to decorate his castle using the Mini Chaos Emeralds. However, upon seeing the released Mini Chaos Emeralds, Dr. Eggman is enraged and chases off the ones that fly near him. However, this only results in him falling out of his car; Metal Sonic flies down to save him. Back at Sally Acorn's Kingdom, Sonic and friends are once again gathered around the telescope to admire the Mini Chaos Emeralds as they glisten in the night sky.
In Sonic Party 9, a new form of gameplay was introduced in this game, retiring the old format seen in the prior eight titles: players move all at once through the board in a vehicle (a car in Chao Road, a magic carpet in Big Boo's Horror Castle and a legged machine in Chao Factory, for example), still taking turns rolling, moving from a starting point to to an ending point. Instead of rolling a die with a 1-10 on it like in the previous games, players can only roll a dice block with a 1-6 on it; however, there are other dice blocks that can be collected, which includes a dice block that allows a 1-10 roll. Instead of trying to collect ringns to buy chaos emeralds, players receive Mini Chaos Emeralds if they pass by them. While doing so, players must also try to avoid Mini Chaos Emeralds, which deduct their current amount of Mini Chaos Emeralds. The player who collects the most Mini Chaos Emeralds by the end of the game is declared the winner.
New minigame types are introduced in the Sonic Party series, one example being 1 vs. 2 minigames against Metal Sonic In this game, the minigames don't appear after every player has moved, but only when a player ends up on any of the spaces that triggers a minigame. Also, when receiving dice blocks, a minigame might pop up after as well. Unlike previous Sonic Party games, where often only the winner(s) of a minigame receives a reward, all minigames are ranked from first to last place and generally all players receive Mini Chaos Emeralds, with players in a higher position earning more Mini Chaos Emeralds.
During a party, there are two board events that are required to occur before advancing: Captain Events and Boss Battles. The former occurs whenever a player arrives on a Captain Event Space. The event differs for each board, but they all allow the players to earn more Mini Chaos Emeralds, though the player that has started the event always has some form of control over the event, putting him or her in an advantage state. As for Boss Battles, there are two Boss Battle Spaces on every board, one near a fortress and one at the end. During the Boss Battle minigames, players must work together to defeat a boss while attempting to increase their own individual scores, as the player with the highest score wins the minigame, which gives more Mini Chaos Emeralds than normal.
- Sonic the Hedgehog
- Miles "Tails" Prower
- Knuckles the Echidna
- Princess Sally Acorn
- Cream the Rabbit
- Amy Rose
- Shadow the Hedgehog
- Rouge the Bat
- E-123 Omega
- Espio the Chameleon
- Charmy Bee
- Vector the Crocodile
Once again returning from previous Sonic Party games, Party Mode involves the players going around the board like with the previous games, but changed due to the new gameplay mechanics of Sonic Party 9. The amount of Party Points that the players will earn is determined by how many Mini Chaos Emeralds they have at the end of the game. However, if handicaps are used, the handicap amount will not count towards the Party Point total; for example, if a player has a 50 Mini Chaos Emerald handicap, and finishes with 100 Mini Chaos Emeralds, they will only earn 50 Party Points. Notably, should a player end a game with less than 10 Mini Chaos Emeralds, 10 Party Points are added regardless of how low their Mini Chaos Emerald count is. This is independent for each player that ends with under 10 Mini Chaos Emeralds (for example, a 4-player game that ends with Mini Chaos Emerald counts of 105, 67, 60 and 3 without any handicaps gives a total of 242 Party Points although the Mini Chaos Emerald total is only 235).
The game's story mode, Solo Mode involves the players traveling across all six boards to defeat Dr. Eggman and save the Mini Chaos Emeralds. Completing Solo Mode will award the player 500 Party Points, and the Mini Chaos Emearld grand total will also be added onto the player's Party Point amount; for example, finishing Solo Mode with a grand total of 500 Mini Chaos Emeralds will award the player 1000 Party Points.
Also, instead of always playing against 3 other computer players in a four-player match on each board, sometimes, the player will play a three-player match against two computers, or a two-player duel match against one computer. The minigames for the three-player matches are Free-for-all minigames and 1 vs 2 minigames, and all minigames in two-player matches will be Free-for-all minigames, adapted for duels. The award system for minigames in a three-player match is five chaos emeralds for first place, three chaos emeralds for second place, and one chaos emerald for third place, and the award system for minigames in a two-player duel match is five chaos emeralds for first place and one chaos emerald for last place.
- Free Play
- Step It Up
- Garden Battle
- Choice Challenge
- High Rollers
- Time Attack
- Boss Rush
- Green Hill
- Emerald Hill
- Angel Island
- Seaside Hill
- Ocean Wave
- Big Boo's Horror Castle
- Big the Cat's Mystic Ruins
- Dr. Eggman's Station
Sonic Party 9 - Sonic the Hedgehog Voice Sound
Sonic Party 9 - Miles Tails Prower Voice Sound
Sonic Party 9 - Knuckles the Echidna Voice Sound
Sonic Party 9 - Amy Rose Voice Sound
Sonic Party 9 - Cream the Rabbit Voice Sound
Sonic Party 9 - Princess Sally Acorn Voice Sound
Sonic Party 9 - Shadow the Hedgehog Voice Sound
Sonic Party 9 - Rouge the Bat Voice Sound
Sonic Party 9 - E-123 Omega Voice Sound
Sonic Party 9 - Espio the Chameleon Voice Sound
Sonic Party 9 - Charmy Bee Voice Sound
Sonic Party 9 - Vector the Crocodile Voice Sound
Sonic Party 9 - Silver the Hedgehog Voice Sound
Sonic Party 9 - Blaze the Cat Voice Sound