A graph I made in the Graph Editor, it replaces the mushroom and 1-UP graphic.
I'll have to reject this graphic. I see some potential in it, but it needs some improvements before I can accept it.
First, you should add a shading to the sprite. If you look in powerup sprites like the ones from Super Mario World, you'll notice that they use shading, even if simple. Take a better look at the pokeball to know how to shade it. My other suggestion is defining a light source, so you know how to shade it. Without shading, the sprite looks off and bland.
Pixel art ain't easy, but this one is a bit too simple. I expect that you can take this feedback and improve the graphic. Good luck.