As you might already know, Valve generously released soundtracks for their games completely free of charge. However they don't let you download them without downloading the whole game, which is not ideal.
It works this way because soundtracks are considered just another piece of downloadable content. But fear not, it is possible to force Steam to download a specific depot.
Here's how you can download Portal 2 soundtrack:
- Open Steam console: steam://open/console
- Enter
download_depot 620 323180(620 is Portal 2's appid, and 323180 is soundtrack's appid) - Wait for it to download.
There will be a message when the download is complete, with a path where you can find downloaded content, something like \Steam\steamapps\content\app_620\depot_323180.
If you go to Portal 2's depot page you will find Portal 2 Soundtrack (323180) Depot there, and you can see its size of 463.75 MB, and that's how big the depot folder should be when it's done.
This process can be repeated for any depot/soundtrack on Steam, as long as you have a license for them.
For your convenience, here are commands for other soundtracks:
- Half-Life Soundtrack:
download_depot 70 323130 - Half-Life 2 Soundtrack:
download_depot 220 323140 - Half-Life 2: Episode One Soundtrack:
download_depot 380 323150 - Half-Life 2: Episode Two Soundtrack:
download_depot 420 323160 - Portal Soundtrack:
download_depot 400 323170 - Portal 2 Soundtrack:
download_depot 620 323180 - Free to Play Soundtrack:
download_depot 245550 323120
If you get Depot download failed : Manifest not available error when using download_depot command, you should use DepotDownloader. Get it from https://github.com/SteamRE/DepotDownloader