For real??? :O
You mean the backgrounds and the title screen? Yeah.
Guess I should add an update. I've isolated all the graphics/sprite/maps/tiles in the rom. For the compressed graphics, I even have all the pointers located and the pointer strings figured out. So relocating them is now possible.
Samples take up about 256kbyte of the rom. The game code itself, is smaller than 256kbyte. A lot of rom (excluding samples and graphics data), is just tables. I found a 12k table that's just used for the speed translation for linescrolls (and the sprites that are part of the BG layer). Anyway, that's good news, in that the code part will easily fit into the base 256k of CDRAM (arcade card ram isn't for direct code use, but everything else).
The other good thing, is that there is a nice chunk of free space on the vector bank (mapped to last MPR). This is always static, so I can put my hook call code there. Free space on in the rom has the text "NEC HE", so it's easy to find.