I think this game would benefit a lot if you replaced all the rule descriptions with special icons.
For example: instead of writing "The color X spread to the squares below and to the left of it." You can just show this instead:And then you can just have the player fill in the icon instead of the big bar.
This will reduce a lot of the UI elements in size and give you more space for the main painting area, which I think should be the focus point. It might take some creativity to figure out what all the icons should look like, but that's the challenge of 'show don't tell', you'll figure it out :D
Indeed a shame of the music being buggy, but at least u had a mute button.
I do think this is a really cool idea though! And well executed!