I just tried the tool once. Just for me.
With Photoshop and in an automated process it would be possible to reduce the graphics to certain colors and palettes. You could make the backgrounds and sprites look like they are calculated on an Amiga, Atari ST or VGA PC. You could make the graphics look like they were calculated in Amiga HAM mode. That wouldn’t be much work without manual optimization. BUT reducing the resolution, parallax scrolling and removing the effects is a lot of work I think. But as I said, I don’t really have programming skills. I’m just a photographer and I know this and that in Photoshop.
Is it possible to write the recalculated graphics back into a compatible file?
Edit: The conversion to 32 colors is finished. Looks good. If I could write the converted.png files back into the.ggpack file, I could play Thimbleweed Park with a virtual Amiga on steroids .
The same would be easily possible with the music and audio files. They just need to be reconverted to 8 bit, 22 khz.