it is actually intended for top-down 3D because that's the game I'm currently working on 😂 it should work with any meshes. The demo uses quads, but there's no reason you can't use a sphere or something else!
It uses DrawMeshInstanced, not InstancedIndirect. Couldn't get indirect to work before the jam, not going to have time unfortunately! That just means there's a cap of 1023 bullets per manager. I don't think you should need that!