Well this sounds kind of silly and complicated I guess, but I was thinking shooting to the rhythm of the map a target that is positioned based on the editing of the map for example, and bullets trying to hit you to prevent you from shooting the target at the right time etc.
I guess stacks, streams and jumps also come to play and can affect difficulty on shooting the targets, and maybe targets also need to be shot with the right bullet based on hitsounds, for example one key on the keyboard for ordinary beats, one for whistles/claps and I guess finishes are like bombs, and the bombs obtained on each mapset is based on the overall difficulty and how many finishes the map has. Spinners can be a massive bullet dodging part on the map.
I guess stacks, streams and jumps also come to play and can affect difficulty on shooting the targets, and maybe targets also need to be shot with the right bullet based on hitsounds, for example one key on the keyboard for ordinary beats, one for whistles/claps and I guess finishes are like bombs, and the bombs obtained on each mapset is based on the overall difficulty and how many finishes the map has. Spinners can be a massive bullet dodging part on the map.