(Old) Games with potential Jazz music?

"Jazz" is a quite large musical category, so your request could attract songs that are much different. Still, I guess you're looking for standard jazz, and I've been able to list a couple of games/tunes you might enjoy and might not have heard of before, since I've ripped them myself. Oh, and all of them are by Western composers, if it makes any difference to you (in relation to you mentioning Jpop and Japanese companies only).

First, from old PC games using the AdLib sound:

- "Toxcity" (from Pushover)
- "Goblins 3 Theme" (from Goblins 3)
- "Trig Enigma" (from FlixMix)
- "Cruz" (from The Incredible Machine)

And here are some others that doesn't sound as old:

- "Hold That Train!" (from Transport Tycoon Deluxe)
- "Night Shift" (from Theme Hospital)
- "The Kitchen" (from The City of Lost Children)
- "Sid's Workbench O'Horrors" (from Toy Story)
- "Alleys and Gullies" (from Toy Story 2)

I've uploaded all of these tracks to SendSpace, if you want to check them out: http://www.sendspace.com/file/2tytvt

If any of them spark your interest, I could provide the full soundtrack(s).

Jam it back in, in the dark.

Just be aware that not all tracks are jazzy, and that this is the "limited sound" version, as Spikey mentioned. With this made clear, here's a download link:

http://www.sendspace.com/file/yngauf

There's nowhere I can't reach.

Yes, there was indeed a PC version, with redbook audio! It's a good thing I liked the movie a lot back in the days, and that I bought that game, otherwise I probably wouldn't have known about this. I guess you're familiar with the SNES version? That one is good, and while it's the same soundtrack, the PC version actually blows it away with the better sound. It's one of my favorites actually; it's very jazzy and dynamic, with memorable compositions.

At the same time, Disney Interactive also released a PC version of "Maui Mallard in Cold Shadow", again with an enhanced redbook soundtrack. I don't know if you ever heard it (if so, propably the SNES one?). It was composed by Michael Giacchino, before he became popular with the "Medal of Honor" series. Like "Toy Story", I find it to be quite enjoyable. If you'd be interested by the rip I did, I could upload it as well.

While I'm at it, I'll also upload the "Toy Story 2" rip. It was composed by the same team (Andy Blythe and Marten Joustra) and it also features some jazz tracks, yet it's more diverse than its predecessor. Check it out if you want and you'll see if there's anything you like.

The download links
Toy Story: http://www.sendspace.com/file/g6oh5w
Toy Story 2: http://www.megaupload.com/?d=E8N0FMXR

This thing is sticky, and I don't like it. I don't appreciate it.

Oh, I didn't even notice that some of the SNES ones were longer. So indeed, it shouldn't be completely dissed.

"Battle of the Mutant Toys" in the PC game is a stage, but could almost be considered as a cutscene, since it's very short and all that actually happens is that you run away from the mutant toys (and if I recall well, you don't even have to touch anything). The following song, "Roller Bob", is used in the next stage where you are on him and roll along, avoiding the various toys and traps. I don't know what's the deal with the SNES version, if that stage is indeed using another song, as I haven't played to it. And I believe this SNES one actually isn't in the PC rip, unless I don't recognize it because of the different sound.

I am a dolphin, do you want me on your body?