HD Version Differences
In the HD remake of Sonic Adventure 2 there a quite a lot of differences between the remake and the GameCube version. The biggest being the absences of the GBA Link Cable removing a lot of features from the game including Jewel Chao and Shiny Jewel Chao being unobtainable in the game through normal means.
In the HD remake of Sonic Adventure 2, the Bulletin Board in the Kindergarten has different text most likely due to the Sonic Adventure 2 site being down. In the GameCube version, the link is still there highlighted in blue text.
In the HD Remake version of the game, due to the absence of the GBA Link Cable, the Chao Transporter has lost all of its menus except the Good-Bye menu used for deleting Chao. The Chao Transporter has also been renamed to the Chao Departure Machine with a new model. As mentioned before, this also means that Jewel Chao and Shiny Jewel Chao are unobtainable in the HD remake through normal means.
Since the access to Tiny Chao Garden via Sonic Adventure 2 Battle is now gone, the Chao Principal's tips have been modified to fit the new release. The Chao Transporter tip has also been renamed to Chao Departure.
In Chao Race, the Party Race menu has been removed and instead found in 2 player mode. The Party Race is also now 2 players instead of 4 players with the extra memory card tab being removed.
Much like the Chao Race, Chao Karate also removed 2 players from the menu and instead put in the 2 player mode.
In the HD Remake, lots of collisions have been edited from the GameCube such as patching the ability to escape the Chao Garden and Dark Garden in the GameCube version. It is also worth mentioning that you can no longer go on top of the Hero Garden diving board in the HD Remake.
Chao Garden Fruit
In the HD Remake, when completing a Chao Race, the fruits will either appear with a water texture or a sky texture. This is a simple port glitch due to the texture ID. In the GameCube version, the fruits always remain the same texture at all times.
Hero Garden Fruit
In the HD Remake, Hero Garden Fruit now gives 20%-30% a bit instead of 10% a bite.
Shiny Two-Tone Chao
In the HD Remake, Shiny Two-Tone Chao look a lot different than they do in the GameCube version. These Chao have a very bright appearance hence their nickname "Bright Chao" making their appearance only viewable in the Dark alignment. See the Bright Chao page for more information.
When a Chao plants a tree in the HD Remake, they appear very small with the rest of the tree invisible which gives the illusion of the fruits floating.