RetroArch 0.9.9-wip3 (Source)
For older releases, releases are tagged on GitHub.
RetroArch is actively developed, and it is recommended to build from latest Git. Source releases are more or less arbitrary snapshots.
Windows binaries (32-/64-bit)
The Windows binaries include full build along with redist (~15MB).
For later updates, it is highly recommended that you download from the Phoenix Updater (RetroArch -> Update). This will reduce updates to ~1MB instead.
These Windows builds also include the RetroArch-Phoenix GUI.
Note that you cannot update from the old SSNES to RetroArch via GUI.
You might get an error that d3dx9_43.dll is not found. If so, DirectX redist is not installed, and you need to install this from Microsoft’s homepages. Alternatively it might work to copy over a d3dx9_43.dll from another PC and place it in same directory as RetroArch.