At first glance, I'd be tempted to guess that the text is compressed using some variety of LZ77
- all of the text that shows up garbled is contained earlier in the string, e.g. the "e " from "the " shows up earlier in "see ", "and" shows up earlier in "quicksand", " spreading" shows up earlier in " spreading", "ng " also shows up earlier in "spreading ", etc.
I'm not really familiar with Genesis hacking, but I see there are some translations
out there, so you could try (nicely!) asking some of those people for advice directly. If all else fails, you should be able to use a debugging emulator, set a read breakpoint on that text, play the game until it tries to display that text, and then trace through the game's code to find out exactly what it's doing (it looks like there's also a disassembly
that might be helpful). This will probably be a lot of work if you also have to learn about the Genesis hardware, ASM, and the debugger's features before you can get started, but the good news is that those skills are all highly transferable to other Genesis games and still pretty relevant for other systems too.