The GBC version runs slicker than the GB version--I actually had to make changes to the puzzle controls based on whether the game is played on GB or GBC! Both versions of the game have four colors, but the GBC version has a nice blue palette (which can be seen in the screenshots). 🙂 Columbrine says the framerate is better on the GBC version as well. One nice thing about the GB version is that is has a special border in the Super GB (which you can also see in one of the screenshots).
Thanks very much for your kind comment! I'm always happy to meet a fellow nonogram fan. 🙂