For context, said collab was quite something out of the ordinary, in contrast to other prior cross-RG collabs in the past few years, with four or five songs from the environmental survival game "Rain World" - composed by James Primate and Lydia Esrig, making it to Milthim, a recent cross-platform, multi-lane RG being heavily...
This roguelite uses the rhythmic system of making actions like movement tied to the music, so it has to be done on beat. In that way it's a lot like BPM: Bullets Per Minute, but this one isn't a shooter....
Or more accurately, part of the new Music Library feature in the recently-released v2.2 update to Geometry Dash, which will also introduce an alternate music source to the home staple of Newgrounds, for both players and custom level makers to play and tinker with, respectively.