Sure. This is something I've thought about adding to BFNSR in the 1.4.8 update BFNSR2. It could be added to the sequel's version of the Classic Mode from BFNSR1 if that ends up being included or maybe as a separate gamemode like how it is in BBCR, and maybe the NULL bossfight would also be available as another bossfight you could select from Bossfight Mode, like how you can select different field trips in Field Trip Mode.