I'm a fan of grid-based RPGs, so I was happy to see that was the direction your game went!
I liked the idea of a risk/reward system fueled on the characters' HP. It definitely made using magic something that needed to be carefully planned and assessed. Neither of the battles were terribly difficult, but then again, they were tutorial stages.
The premise of the story has a lot of promise! I like the idea of a menacing magical girl forcing the characters into succession for her. There's not much there yet beyond that, but it's definitely off to a good start. Also, cool to see the theme integrated into the gameplay mechanics!
I like the art style of the characters, and the in game sprites. The UI looks good and works well too. The backgrounds/levels are a bit on the sparse side. Not sure if that's the plan, or a limitation of the jam period.
Overall, really nice work!