Every Geometry Dash version until 2.2 using the download_depot command in the Steam console and SteamDB manifests from oldest to newest.
My version of how to play these versions. Let me know how I can improve it by commenting in Issues.
As of February 11 2024, the first 3 versions cannot be played by me.
NOTICE: Stereo Madness and other levels may show a percentage of the level played. It is probably because you have Geometry Dash installed with Steam.