RobTop Games has confirmed that you can use more than one song in a level in Geometry Dash 2.2. This means players will be allowed to use more than one song in their levels this coming October once update 2.2 releases.
RobTop shared a video that showcased the feature in action. In the video, it shows an example 2.2 platformer level with the song Stereo Madness. After a while, Stereo Madness slowly fades out, and after a sound effect plays, a new song starts playing.
This is a feature that many were hoping for. Platformer levels work best with multiple soundtracks, so with this featuring coming in 2.2, it will lead to amazing platformer levels beyond anything we've currently seen in the Geometry Dash 2.2 private server.
It is unknown whether this feature will be available in normal levels as RobTop only confirmed that platformer levels will be able to use it without commenting on its wider availability.