I like the idea of Mask. But was click a drag not necessary ? i felt tired in finger lol.
In the falling fireball level. You could have use the Mask feature by putting a large wave of fireball then the player need to find the fake one for him to dodge. I was able to dodge most if not all of them easily. And beside, i suppose the endgame trigger is when you get hit ? well that took me a while, as i died by accident too.