This is a beta patch that replaces all the 8-color enemies with their 16-color WonderSwan counterparts. It should be applied to a headerless ROM of the 1.1 US version (1.0 might work - never checked). At this point the enemy battle graphics part is pretty much finished. A few small things could use polishing, but everything seems stable so far.
Feel free to post feedback, bug reports, and the like.
If you’d like to incorporate this into a hack of your own and have questions, feel free to ask.