Cambouis de l'Atari

Hi everyone, Yes, it's really a great cartridge. I was able to play a little now (cave D1, 2043 points ). I noticed something, I wonder wether it's a bug, or an event that I'm not aware ? I sometimes have the background that "sparkles", a bit like the starfield in Cosmic Ark. It happens generally once on each cave. I'm playing in pal 50 hz btw. And this was my first post