Dreamcast Conversion is a mod for Sonic Adventure DX PC that brings back Dreamcast levels, textures, object models, special effects and branding.
Homepage: http://www.moddb.com/mods/sadx-dreamcast-conversion
To install Dreamcast Conversion you can use SADX Mod Installer that sets up SADX Mod Loader and downloads the latest versions of mods automatically. The installer can also convert the Steam version of SADX to the 2004 version, which supports the Mod Loader.
SADX Mod Installer: http://www.moddb.com/mods/sadx-dreamcast-conversion/news/new-mod-installer-now-available1
Alternatively you could download Dreamcast Conversion for manual install from the ModDB homepage or get the latest AppVeyor development build from the link below.
Latest development build: https://ci.appveyor.com/api/projects/PiKeyAr/sadx-dreamcast/artifacts/Release/DreamcastConversion.7z
Changelog: https://dcmods.unreliable.network/owncloud/data/PiKeyAr/files/Changelog.txt
Developer's Twitter: https://twitter.com/pkr_sadx
Related mods:
Dreamcast DLCs: https://github.com/PiKeyAr/sadx-dreamcast-dlc
HD GUI 2: https://github.com/PiKeyAr/sadx-hd-gui
Sound Overhaul 2: https://github.com/PiKeyAr/sadx-sound-overhaul
Time of Day: https://github.com/PiKeyAr/sadx-timeofday-mod