I played iim and it looks like it's scrolling at 25 fps, but the preview videos for iio are clearly scrolling at the full 50 fps. Is this some new scrolling tech in iio?
Congratulations on solving the issue!
(I had suspected that it might be NTSC, hence my question about the game being slower.)
Yes, the game is indeed difficult, but that's mostly because it's a single level (zone, in the game's terminology) as it had to fit in 16 kB. QUOD INIT EXIT IIo will have 5 zones of increasing difficulty.
Enjoy!