DotNet Core 2.0 - Runtime
DepotDownloader by SteamRE
Download and install the DotNet Core 2.0 Runtime
Download the latest release of DepotDownload and extract it to a folder on your desktop
Open up one of the following: Windows: Command Prompt or PowerShell | Linux/Mac: Terminal (Make sure to run as administrator)
Next you're gonna want to navigate your terminal to the directory where you extracted the Depot Downloader.
You are now ready to download the game files
dotnet DepotDownloader.dll -app 258550 -depot 258551 -manifest 4262994212477530803 -dir C:\PATH\TO\OUTPUT\
CLIENT: Note: This requires you to own the Rust on steam, also it will prompt you for steam mobile authenticator code if enabled
dotnet DepotDownloader.dll -username Your-Steam-LoginName -password Your-Steam-LoginPassword -app 252490 -depot 252495 -manifest 5597306068983386325 -dir C:\PATH\TO\OUTPUT\
All the necessary game files should be downloaded to the directory you chose with the -dir switch.
Both parameters provided for server and client will download the last build of Rust Legacy for x64 Windows.