That’s weird, it should work already since the game exe should receive the same subsitutions as the rest.
But requiring the CD to play the game would be rather annoying, have you tried merging the CD content in a folder in GAMEDIR then launching the game from that location?
I fixed the previous installer - it was also possible to start the game without the CD.
But the $DISC parameter isn’t working. ‘exe:’ seems to look in the installation path. Using exe: $DISC/teaser.exe in the installer results in this error message: The file /home/username/Games/math-blaster-ages-9-12/$DISC/teaser.exe could not be found.
But I think this is not really urgent to fix this.
The $DISC/path/to/exe would have worked if if had been in the game section of the installer, now it will be correctly applied even when provided by the exe directive