A few things that came to mind was that please use a higher poly sphere so you dont see the edges, the other thing was the speed of things.
It feels like it’s first fast speed in the charge up, then slow-mo when it’s charged and then normal when he shoots. I would make it so that it’s the fastest in the end, i.e make the flames travel backwards faster because atm it feels like they move slower then the sphere shrinks at the start.
If you want the changes in speed I would try more extreme changes in speed and then tweak it until you hit the right spot. It might also be that it’s just something missing in the charged up state, if you add some movement in the charged ball it would probably remove the slow-mo feel.
But then I don’t play fighting games either so not sure how things usually look
I’d also probably try to use less gradients in the trail for the buildup and the projectile or switch to masked with them, so that they keep the same style as the other parts.
Might be worth looking at this for timing and speed
Overall I like it tho, looks cool!