Guide: https://steamcommunity.com/sharedfiles/filedetails/?id=299808681

Link to Download: https://sadxmodinstaller.unreliable.network/

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Features
Dreamcast Conversion
Includes the incredible Dreamcast Conversion mod by PkR. This project aims to return the PC version of Sonic Adventure DX to it's appearance on the original Sega Dreamcast. This includes the restoration of the palette lighting engine, as well as ports of the Dreamcast land tables, level models, and textures.

Resolution Options
Use any custom resolution. With “Windowed Fullscreen” and “Stretch Fullscreen” (enabled by default), you can specify resolutions larger than your native which will downsample.

Improved Graphics, Sound and Fixes
Texture filtering, Mipmapping, better sound and an extensive range of layout and bug fixes, created by the community.

Mod Support
BetterSADX includes and relies on the latest version of SADX Mod Manager, which provides a clean entry point and effective way to manage mods for the game! All of BetterSADX is fully modular, meaning, you can configure and tweak it here to your heart's content.

Full Controller Support
Includes the latest version of the Input Mod by SonicFreak94. This provides improved support with use of the right stick and trigger buttons. It also includes Smooth Cam to give you a smoother first person camera.

We now support the Steam Controller as well. Here's a profile for BetterSADX, upvote it if you want.
steam://controllerconfig/71250/1957635702

Super Sonic in Action Stages
Once you’ve completed the 7 main story modes, you can play as Super Sonic who is faster, invincible and can run along most water. He loses 1 ring per second and will lose the power once his ring count hits 0.

To activate:
Make sure you've completed the Super Sonic story at least once.
Play as Sonic.
Collect 50 rings.
Jump and press the B button to transform into Super Sonic (or to transform back).
Please Note: Some stages and items/set-pieces (which force you to spindash) will auto-transform Sonic back to his normal form to stop the game from crashing. If you are unable to transform for this reason, Sonic will say "Huh?".

Dreamcast DLC
The wonderful DLC mods by PkR! These mods allow you to experience the original Dreamcast DLC at any time by toggling them from the Mod Manager! Simply open the game and choose configure to bring up the mod manager.

Playable Game Gear titles
The Game Gear games from previous SADX releases are back.

Sonic the Hedgehog
Sonic Drift
Sonic Chaos
Sonic Spinball
Sonic Labyrinth
Sonic the Hedgehog 2
Dr. Robotnik's Mean Bean Machine
Sonic Triple Trouple
Sonic Drift 2
Tails' Skypatrol
Sonic Blast
Tails Adventure
You can unlock them by collecting emblems and beating missions in Mission mode. It is recommended you run the game in 640 x 480 if you plan on playing these.

Seamless Integration
You can enjoy all the features just from running the game via Steam and choosing Play or Configure, and in addition, this also supports Steam Achievements.

Discord Rich Presence
Show what you're doing in-game to your Discord friends and servers.

Link: Oldunreal's 227 Patch

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Link: BO1, BO2, MW3, WaW redefined. - Plutonium Project

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Dedicated Servers

Modding Support

Improved Security

Controller Support