When Sonic Adventure was released on the Dreamcast, Sega regularly uploaded content onto the in-game site that would unlock already programmed, yet hidden, data. Sega had many downloads for Sonic Adventure as it was a launch title for Dreamcast as well as the Dreamcast most popular game (2.5 million as of June 2006). Most of these downloads were events and challenges that mostly took place in Station Square. These events were to celebrate an actual event or for competitions that were hosted by Sega.
Dreamcast Launch PartyEdit
One of the first things made available was the Dreamcast launch party in Station Square. Around the city, banners and balloons featuring the Dreamcast emblem and logo were set up and would thank people for supporting Sega and Sonic Team, as well as pointing out that there was plenty more in store. While the posters and language varied (Mainly Because of the Different Swirl Color), it is generally the same Dreamcast posters and balloons that thank you on behalf of Sega and Sonic Team when jumped at.
From October 19, 1999 to December 28, 1999, Sega released Halloween decorations for Twinkle Park. Scattered around the level, graffiti has been tagged on the walls and floors wishing the players a Happy Halloween, while Jack-o-Lanterns in witch's clothing danced around. "Trick or Treat" would occasionally come up while walking on the graffiti. Station Square will have posters advertising Twinkle Park's Halloween party.
From December 17, 1999 to December 28, 1999, this download places Christmas trees outside the station and also at the town center. Jumping at them will give a festive message as well as changing Station Square's theme to the Acapella version of Dreams, Dreams from Christmas NiGHTS into Dreams. Heading to the other parts of Station Square will reset its theme back to its usual theme.
With the year 2000 on the horizon, Sonic Adventure is given a Millennium Ring that floats around Station Square and two in several stages. Upon touching one, you are given a message wishing you a happy new millennium while being asked to support Sonic during that time. As this occurs, Palmtree Panic Zone's Japanese theme plays in celebration. There are also various posters around Station Square with the folowing messages: "Knuckles digging through 2K!", "Tails smiles through 2K!" and "Sonic runs through 2K!".
A new track was made available for download, titled the "Samba GP." The track was released to celebrate the arrival of Samba de Amigo although, oddly enough, the track had little to do with Samba de Amigo aside from the fact that the track uses an instrumental version of Sonic R's "Super Sonic Racing", which is a playable song in Samba de Amigo. Upon completing the track, you could save your score and upload it online to compare against others. Also worth noting is that this was the final update to the game that included any actual changes to the main game itself. Afterwards, Sega began to focus on Time Attack contests within the regular game itself.
AT&T and Official Dreamcast Magazine teamed up to release three time attack contests. One involved blazing through Speed Highway as Sonic, the next involving Knuckles collecting treasures in the Mystic Ruins and the final one involving Tails surfing through ten specially marked gates in Sand Hill. This was available only to the US. Prizes were awarded to the quickest scores. A total of fifteen winners would be awarded 1-Year long subscriptions to Official Dreamcast Magazine, nineteen winners would be awarded a Dreamcast game, and five would receive an AT&T Premium Package for a whole year free. It is likely the grand prize received all three. This contest ran from October 29, 1999 to November 19, 1999.
Reebok DMX CompetitionEdit
Contestants from across Europe could download a specially designed version of Emerald Coast. Gamers are required to retrieve five pairs of hidden Reebok DMX trainers which Dr. Eggman has stolen from Sonic's wardrobe, while still competing for the fastest completion time. Times where then uploaded to Sega's servers so that contestants could gauge their rating. The winners would then be notified via e-mail and their names published on the Sonic Home Page and on Dreamarena at the end of the competition. The prizes included a personalized Dreamcast pod and £1,000 worth of Reebok sportswear. Neil Riddaway won the challenge by finishing in 46.09 seconds.
Christmas Trees in Station SquareEdit
Released sometime around the christmas season of 1998, this DLC scattered christmas trees around station square. Touching them would reveal a japanese message and various christmas songs, depending on what tree the player touches.
Hedgehog Hide and SeekEdit
Released on February 12, 1999, Famitsu held a contest where players had to track down 5 pictures of actual hedgehogs that you must find around Station Square. To start the game, one must jump to the red sphere in front of the Train Station. Once all pictures are found you must go into the station and jump at the light blue sphere to finish the game.
Yukawa Senmu QUO MiniGameEdit
The DLC consisted in using a character to run around Station Square and Mystic Ruins areas and try to collect 6 Mr. Yukawa cards (3 in each area) in the shortest time. This Was a promotion from 99/1/22 to 99/2/22 where 50 winners will get a 500 yen QUO card with a picture of Mr. Yukawa, (Yukawa Senmu, Senmu meaning the title of director or manager) the Sega manager on the Dreamcast box. The QUO card is a universal pre-paid card that can be used in 10,000 convenience stores and other locations in Japan.
Special Chao that were available in the Black Market in the Sonic Adventure WebPage. Only 3 were available for Sonic Adventure and only in Japan. They Were: Emerald Jewel Chao, Sapphire Jewel Chao, Ruby Jewel Chao.
Voice Pack (S.A. International)Edit
A Special Version of the Voice Packs Released for Sonic Adventure International. The Main Difference Between the 2 in that this one includes every voice files compiled in one file. The various voices are activated randomly in the menus.