Making a repacker isn't impossible, rn I only have an unpacker made. It's just unlike unpacking, repacking needs more time to ensure all the data is properly created. And this isn't a big project I want to spend a bunch of hours in atm, nor do I...
U_## means unknown opcode.
S means not tied to an opcode and needs extra work in the background to parse.
O means known opcode.
Game uses SHIFT-JIS, no idea how well ASCII characters will look with the default font.