I think the reason most people (including myself) found it hard to understand was the different colors - most tetris-like games involve matching similar colors.

I think the reason most people (including myself) found it hard to understand was the different colors - most tetris-like games involve matching similar colors. Once I understood that the colors represented size and nothing else, I got it almost instantly. I'd consider a slight redesign that removes color as a factor - or maybe make them all start out the same color.