Add this, if you get to a certain amount of score in the game, you enter a boss fight

I think it's not the color which should be changed but rather, how many colors player see at certain level. Right off the bat, there are so many colors and lines, making it look complex and hard. My suggestion is to start with fewer lines and colors first, then as game progresses increase one of them to increase difficulty.

 OTOH what makes it not appealing to me is lack of reward or reaction from swiping correct lines. There should be effects played when player swiped correct lines and other effects when swiped wrong lines.