I'm not referring to the sound, but rather, to its operational structure and MIDI specification, which, compared to the MT-32, are positively dinosaur-like.
What are the difference to MT-32 in MIDI control for the FB-01?
So, this is a little bit more inclusive, but...
Why the FB-01 is a Sucky Multitimbral Synthesizer(When compared to the MT-32)8-note PolyphonyThis is, perhaps, the biggest weakness when used as a multitimbral synthesizer. The 8 voices can be spread out, in static fashion, amongst the eight instrument channels, but that's it - the FB-01 lacks the dynamic partial allocation abilities and polyphonic assign modes of the MT-32.
Non-standard Program-Change Range and Bank-SelectionNot necessarily a problem for sequencing/MIDI-playback, but on its own, bank selection with the FB-01 has to be performed either from the front panel, or via SysEx. To be fair, a stock MT-32 requires SysEx to access timbres in the Memory group, but at the same time, I can turn on the MT-32 and select any of the built-in timbres directly from my keyboard. In addition, the MT-32 allows for complete redefinition of its full-range Program Change map.
Rhythm ChannelYeah... What rhythm channel? With the FB-01, each drum-component voice requires its own instrument channel. The MT-32, on the other hand, has a ridiculously flexible rhythm setup, allowing for individual timbre/key re-mappings.
PanpotHard, L-C-R panning in the FB-01, compared to the 15-position soundscape available in the MT-32.
I like the FB-01 pretty well, and have two in my setup that sound fantastic when run through an effects-processor. It's just that, in my opinion, they're terrible multitimbral instruments, and wonderful performance-based instruments. Portamento control? Check. Monophonic mode? Check. Aftertouch assignment? Check. - All advantages the FB-01 has in this regard.
In that vein, I suppose the Atari ST versions of some of these games, which support other Casio devices, could have their patches extracted. Then the issue would be writing a driver for the PC.
Disappointingly, the Casio "support" that the Atari ST releases have, if you want to call it that, doesn't include any unique use of the Casio synths at all - rather, it's like GNRCSND.DRV for Atari computers, where the user has to pick the voice(s).