I revisited my Return to Zork work again this past week a bit. Mostly because my FM-Towns version arrived! :D It's been a while since I've looked at the game... have to go way back in the blog to find some posts about it.
I put the disc in as soon as I ripped open the package and looked at the files. To my surprise, ScummVM detected it immediately! It seems that we have a collision here... the rtzcd.red file has the same md5 of the first 5000 bytes and the same size as the English CD v1.0 version. Furthering my amazement, it turns out there's three other rtzcd.dat files on the disc (an rtzcd.dat is also in rtzcd.red). One in the base directory, one in the "RTZFM" directory and one in the "RTZ9821" directory. Turns out the one in the base directory is for DOS, RTZFM for FM-Towns and RTZ9821 for PC-98. Three-in-one, yay! I added the detection for all three.
The three versions all show up with messed up text. It seems to use the "KROM" file included on the disc for the font. I proceeded to install the DOS version using DOSBox. In some strange oddness, the game failed to find the two resource files: it was searching for the floppy names of the files. A quick rename and the game started up, though still failed to play the videos off the CD. The Japanese text does work there, so I'll have a chance to compare eventually.
All this RTZ stuff got me to pull my PlayStation version out again (Yes, I have 5 versions now: DOS, Mac, FM-Towns, PlayStation, and Saturn :P). The game currently errors out when starting up in ScummVM with failing to load the cursor bitmap. Couldn't make out too much of the format yet, but it seems to have 8 characters in the beginning with some sort of numerical text followed by possibly a uint32 size or offset.
Anyway, I got to looking at some of the other files on the disc (possibly again, I don't remember what I'd done in the past). There's a ZORKX.INF/ZORKX.XAI pair of files that contains the XA ADPCM audio (which we luckily support already!). The INF contains text entries of the filename and some numbers (tracks?) into the XAI. In the DISK1/DISK2 directories, There's the [dirname].INF and .STL files that are similar, except they contain PlayStation Stream videos.
In the MSG2/MSGJ folders, there's a bunch of TIM files and BS files. Hopefully no pun on the latter. The TIM's are standard PlayStation images. I know there's a bunch of tools out there for them already, but I wanted to write my own; it's simple enough. It can now be found here and supports both 4bpp and 16bpp TIM's. And my favorite of the converted pictures: