I'm playing Quest for Freedom (built in the 1.90) in the 672 build.
In the second room in level 5, after you get the flippers, you swim to a wall on the right. It's a walkthrough wall, and as soon as you get out of water, the game freezes.
The menu will still drop down and you can switch items, you just can't use them.

Swimming through walkthrough walls, you say? Okay.
Actually you don't swim through the wall, Link emerges from the water when he gets to the wall.😊
I have some other backward compatibility issues that I can put on here.
Dev's are these something you want to look at, or are these low on your priority list?
I'm not experienced enough with zquest to be any help there. This is the only way I know that I could possibly help. But I don't want to 'get in the way' of the progress your making, of a stable version.
Those are the things that need fixed in order that there be a stable version. 😉
You can move to exterminated.
Thanks _L_ 😊