I'm making great progress with the disassembly. I've finally discovered the routine that lays out the object sprites. Now I can get MaSS1VE to import the object sprites directly from the ROM and I don't have to hard code each and every object myself.
I've been debating for a while now if I should create my own Z80 assembler in VB6. It sounds insane, and it is, but I'm running up against major limitations of the assembler I'm using (WLA DX) both technical and syntactical.
Undertaking such a task obviously eats up time and puts MaSS1VE progress further back, but it should be best for the long run. Direct integration of the assembler with MaSS1VE will mean the possibility of baking code editing into the editor as well as possible pseudo emulation to allow a playtest-in-editor feature.
I had assumed an idea as mad as a Z80 assembler written in VB6 couldn't possibly already exist. I was wrong! http://sourceforge.net/projects/z80toolsforwind/ This might help me make more rapid progress, I'm looking forward to seeing what I can do with this.