Dear lord, what a buch of newbie noobs! (;
The music for Turrican on the Amiga was written by Chris Hülsbeck, in a format called "TFMX". The only reference i could find was on German Wikipedia. I'm not sure how the music was adapted to other systems, but i think the same technology was used for the PC port(s).
TFMX is more a tracker format than a synth one. I'm not 100% sure, but i think i read somwhere that the TFXM format would allow samples and synthesized sounds to be played back (synth sounds are, after all, just commands to play certain waveforms in certain frequencies at certain lenghts - this should be possible with every sound chip, within its technical limits). I believe the correct techincal term for what i call "synth" is "FM" (Frequency Modulation).
Oh, and btw: i don't know what Mr. (or Mrs.) Know-It-All leileilol wants with his/her PCM (Pulse Code Modulation). As you can read, PCM is nothing more than a technique to store and playback digital sounds. I'm not the technical guy, but to me, this sounds like a way to "encode" digital sound, similar to WAV or MP3. The point is, "PCM" is not a method of sound creation, it's a method of storing digital sounds. Sorry, had to get that off my chest. (;
OK, to get back to the original post: so "FM synth music" is any music generated by a computer chip, without using digital samples. So i'd say, if you're looking for impressive FM synth music, look at the C64 SID sounds! The cheap and simple piece of silicone called SID was able to produce incredible music, in the right hands. Don't go for an emulator, btw - head over to SOASC (the SOASC project is crazy - make sure you check out the pages with the descriptions of the hardware that was used to create all the MP3 tracks) or the SID Recording Archive for authentic sounds. Some very good composers are Rob Hubbard, Martin Galway, Maniacs of Noise, or alot of people from the demo scene, like Mitch and Dane, or kb.
Btw, if you want to know what a PC can do with FM synthesis, look for a piece from kb called "Candytron" (it's available as an MP3), or download the Windows demo "fr-030: Candytron" by "farbrausch". Both the demo and the soundtrack are amazing! The demo runs OK on slow-ish P4 machines, and it's only 64k (!).
In case you didn't notice: i'm a complete computer music (as i call it) nut. I have a _huge_ collection of game soundtracks, mods, and synth tracks converted to MP3. It's amazing to be able to see how that kind of music has progressed over the years.