This page offers a walkthrough of the level Battlerock Barrage in Battlerock Galaxy. This is the third galaxy you can unlock in the Fountain Dome, it will cost 12 Stars to unlock it.
Collect the Pull Star Pieces
Your first task during this level will be to collect all 5 of the blue Star Pieces found on the small flying saucers. There will be some on the topside and underside of the saucers. Once you have those, you’ll be able to use the Pull Stars to pull yourself into the Launch Star that will take you to the next area.
You’ll then be transported to a small saucer with a purple jump spring. Use that to get to the saucer above you. Walk to the topside of that saucer and you’ll find a blue screw. Spin on it using Y or shaking the Right Joy-Con to screw it. When you do this it will activate the saucer and you’ll begin the main challenge of this level.
Your next task is to stay on the flying saucer and avoid the cannonballs being blasted at you. You’ll be able to move to the bottomside of the saucer if you need to avoid the cannonballs, but be careful not to hit the electric balls that are rotating around the saucer’s edge. In addition to the cannonballs, you’ll need to move to opposite sides of the saucer if there are electric fences in your way. It is relatively straightforward but some sections may require quick movement to move down to the bottom side of the saucer and then quickly moving to the side to avoid an incoming cannonball.
Guiding the Bullet Bills
When the flying saucer has stopped, you’ll come to another saucer with a trapped Power Star. Next to that saucer is another one with 4 cages on it. To the right of the saucers are two Bullet Bill shooters. You’ll need to get the Bullet Bills to notice you and then they’ll target you like a missile. With this, you can guide them to crash into the cages. First, you’ll need to get the Bullet Bills to crash into the four other cages, filled with mostly Star Bits, so that you have a clear path to the caged Power Star. Then, guide a Bullet Bill towards the cage on the first saucer to release the Power Star and complete the level.