64 kb of VRAM is a lot of space and I feel like there must be enough space at least for two distinct players and all stage enemies, if not you could probably do something, anything other than trying to pretend that the CD is part of a hucard like it does stopping every 5 seconds or so to """""bankswitch""""".
They probably did the least amount of effort to make the hucard code run on a CDROM and that's infuriating because it could be much better.