The planets could be a little bigger. The map area reads as much larger than the current spherical representation of the planets, which is distracting. Also, because the planets are so small, it always feels like you're on either side of a hill, even when you're right next to an enemy.
Attack range could be longer. Right now it feels like you have to be almost standing inside enemies to hit them. I wonder how it would feel if you couldn't pass through enemies.