You mean run them side by side ? No, I did not do that. I played the ported game on my Mac only. The movement feels right based on my thousands of hours playing the original. There was only small tweak I had to make the trampoline jump, but everything else ported so smooth. I think the decision that Claude made not to use Godot physics and just port everything as as, made the gameplay feels right without much tweaks.
Have you been following the videos on Youtube of the Amiga port of Sonic?
Their approach to replicating the behaviour is to run the original game logic. The display has to be totally rewritten but they had the advantage of 68k for both machines.
I don't know of any games that used the blitter for calculation like some programs did for MFM decoding, that might have presented quite the porting challenge.
No, I have not. I will definitely check before releasing the Amiga port inside the Steam. I think that would be the right approach, especially if you are porting a game you have not played enough. I did use blitter for all graphics. Now you mentioned MFM, I remember I wrote some disk copy protection code back in the day that leverages MFM encoding. I will check if that code is still around.