I've never seen the demo, does it work in other emulators? Your emulator? Any idea what's wrong with it?
I'm glad you asked. Yes, I'm quite sure about what's going wrong there.
The two effects (the Tetris part and the scroll part) that broke on WinAPE rely on the same CRTC trick which is about abusing the Reg6 (Vertical Displayed).
The demo use a behaviour that is unique to the CRTC Type 1 chip: When Reg6 is set to 0, the CRTC Type 1 ALWAYS display border.
It's really simple when you know about it.
It's implemented for sure in CPCBox and ACE (and probably in some other emulators too).
But really don't trust emulators.
Try the demo on a real CPC and see it for yourself.
This is what you should see for the Tetris part:
[attachimg=1]
And for the text scroll part:
[attachimg=2]