Originally Posted by Mr. Ksoft
They don't really sound very close to FM synth at all. And I'd know because I have an old PC with FM.
I think a better comparison would be made to 1992-1994 module scene music, mostly the ones made in Scream Tracker (.s3m files) or even older MOD modules. They seem to have a distinctive instrument set (possibly one included with the program back in the day, or just a heavily traded and popular one) that is very similar to the ones used in the DKC games. This is extremely noticable in the the lava level song from DKC2 (I think it's called Hot-Head Hop if you try and look it up), where the nearly every instrument sounds like it's from this "standard" module set.
It would make sense if they did use them, anyway. Both the SNES and Scream Tracker supported 8 channels, and the way the SNES plays back music is very much like playing a module.