For what it's worth, the early demos required the OS version they were made against, especially pre-release amiga stuff (v27, v29, although i've gotten some of the v27 demos to work with v29 kickstart, iirc).
1.1 was another funny one. Some of the older software requires 1.1 or 1.0. MusiCraft is one that comes to mind. It was made for 1.1, and might work for a little while on 1.2 or newer, but it has some graphics glitches. Same with Instant Music.
It's been a very long time since I played with this stuff, so i may be talking out of my butt here.
Related; Does anyone have the pre-pre release version of MusicCraft? So far as I can tell there is one common version out there, and one rare, earlier version which has a version of "Spanish Flea" that I've not heard since the late 80s. (Yes, there are other versions, but I want to hear that particular one.) If anyone has leads on this, please let me know.