I had mentioned working on a MSX2 RPG last year called Crimson (a kind of eh game but a relatively small game in text volume).
The biggest issue I had was that I couldn't find the graphics in order to add a few needed characters to the game's font.
Well, after some digging a Disassembly log made with bluemsx, I managed to find the code that initially dumps the graphics into VRAM.
And it was simple to write a decompressor.
The problem is that I don't think there's a tile editor for MSX graphics.
(and it might even depend on which of the VDP graphics modes the game is using)
This game at least in running in what is effectively a 16-color bitmap mode. (I'd imagine the VDP's tile modes use a different format. Possibly a planar format like consoles, except the bit planes cover the entire tilemap instead of a tile-by-tile plane?)
So a hack around that problem was to convert the graphics rips to Genesis, and then convert back. A bit of bugfixing left to do, but it's just about there. (I had the idea but it took quite awhile to figure out the right way to swap the Address bits so the bytes get swapped the right way.)
(at least in said bitmap mode, the graphics are stored as 4bpp linear 256 pixels (128 bytes) wide.
I probably could edit the MSX tiles directly in Tile Molestor but as great as TM is I don't want to let Java clog up my PC just so I can run it (it was a decade ago when Java was actually regularly used. I guess it's kind of like Adobe Flash, once we installed it and updated regularly. Now I haven't updated in awhile and I'm not even noticing it.)
I think I have the graphics compression and conversion programs working. Had some issue with the recompressed data not verifying matching to the ROM but it turned out to be a dumping error. Fixed and it checks out. So graphics issues should be solved.
(it seemed kind of odd that the game would have an RLE run of 0 bytes. I understand 1 is needed to encode a byte of a literal value matching the RLE keys. And that it occurred in a block I was already sketchy on made me double-check. What was bad is that the block turned out to be the ending graphics, so I'm glad I had a savestate to check it quickly.
)
One thing I am thinking of doing is to make an optional extra patch to this game:
remember the Casey Bat from EarthBound which is very powerful but has a 3 in 4 miss rate?
Well how it would it be like to play a game where that hit rate is pretty normal?
I suspect it has to do with the enemy's DEX compared to the player, as I seem to rarely miss against weak enemies but regularly miss (at least as often as I hit) against comparative enemies. I'm thinking of making a patch to curve that down and see if it improves. Considering damage is already extremely random (and enemies have like a 7 to 3 party size advantage), I don't think reducing the miss rate is an unfair move.