I think there's an interesting idea there, but I think a few small tweaks would make it much easier to enjoy. The biggest thing for me is that the timer makes it really hard to explore the mechanics and come up with a plan. It takes me some time to understand what a new color/character does and how it interacts with the other colors, but because of the timer I don't get much opportunity to explore. If you had more tutorial levels, so that we already understand the mechanics better before you ramp up the difficulty, I think I would enjoy it a lot more. Still, it's a fun idea :)