Well, maybe I should have mentioned it earlier, but whatever. The black color is only visible through the polarizing film. When I took it apart, I could see the intended shapes on the LCD as well as this liquid, no obvious crack, so I doubt it's oxidation, but still probably not fixable.
However, maybe someone more knowledgeable than me could still use the LCD to take pictures of the shapes using some kind of polarizing filter? How are the shapes dumped (for a lack of a better term) anyway?
Anyway, any takers for this game let me know, I'll ship it. Willing to get this thing dumped even if it's only for confirmation of the ROM that's floating around.