One comment about the text output of some characters. I like the idea behind given some of the characters their own, consistent color text that goes with their overall character design, but it's current implementation falls short on smaller, mobile screens. Some of the text genuinely becomes illegible, especially if the color is close to the overall background color at the time. There might also be some colorblindness issues, too, but idk about that and it's just a hunch. My suggestion would be to either add either a mode to make all text the typical "white with black outline" or just "white", or otherwise add ways to improve the contrast between the text and it's background.
Another thought I had is the boss battles seem to largely be "dodge ball" games. Nothing wrong with that, but it can be tricky if you're on a touch screen. Maybe add an indicator to show the safe/safest squares for any given wave. Then it turns it more into a "quick time puzzle", where you need to not only react to touching the correct map square in time, but also still be close enough to reach it in time. Otherwise, the boss battles on mobile are really just a game of "did you bring enough healing items"?