Yes it is "midi". X68k has its internal synth but is also midi compatible. Arcade has only its internal synths chips and there is no interfacing possible, therefore no midi. Many vg composers at the time preferred to work with midi if possible and take advantage of the various advanced synthesizers available through midi.bcass wrote:That X68K rendition sounds like MIDI (in fact, it almost certainly is some sort of MIDI if you can route the sound through different sound devices). There's less complexity to some parts of the X68K versions. The PCE version is just an enhancement of the PCB version. The PCB version is almost certainly not MIDI, hence the other versions sounding like rough approximations rather than being accurate note for note. I used to play arcade Gradius II religiously (it was one of my first 1CCs back when it first came out in the arcades) so I can instantly recognise when approximations are being used for note data instead of the original data.
Most of these professional video game music composers used roland sound modules as their tool to work their compositions on. There is a special configuration on some x68k games that lets you chose which sound card to use from a list. Those choices are usually cards for which the composer/arranger made a specific version of the music and among them you usually have one sound card that the composer used as his favorite one. If you have this same sound card and you configure the game to use it, you hear the music exactly the same way as the composer/arranger who made it. By using roland sound modules you are usually using the same device as the composer and you are listening to the music as it was really meant.
For example, when Robert prince composed the music for DooM, he was using a Roland Sc-55. Therefore playing DooM with any other sound card is only an approximation.
I know that the X68k port of Gradius 2 has a soundtrack arranged specifically for one of the roland sound card. I am not sure which one exactly yet, i think its either the Mt-32 or CM-32L, maybe even CM-32P, and maybe even something else, Japaneses are known to have used some of the weirder cards for games ( by opposition to western devs. who nearly always made things with either Mt-32 or Sound canvas).
The main thing anyway is that im not a gradius arcade purist so the concept of one version being an original and the rest being copies is not relevant to me. I am not as familiar as you with the arcade ost and it is possible that as you say some parts have more complexity to them. The pce is certainly an improvement over the arcade but then those early redbooks are usually a midi version recorded through a synth/sampler and then mastered for a more "professional" finish.
If my favorite version is not the arcade original its no big deal for me, as long as the arranged midi version i am hearing is itself of original quality ( as meant by the composer). Im still curious about something, was the x68k version arranged by the original arcade composer or someone else? Should not be too hard to find out.
*edited couple typos
The last one even comes with a floppy with midis for the roland sc-88pro, thats too awesome 
