Thank you! The visual effect I used in the game is called "metaballs". It seems very impressive but it's actually not that complicated once one knows how it's done. I left some links in the game description if you are interested.
Also thank you for the tip about the colors! I used a very subtle color difference for aesthetic reasons but it didn't occur to me that in fact this is a problem for people with color-blindness. I will try to keep this consideration in mind in the future!