Thanks! There's actually no definitive winning strategy. It relies mostly on dexterity and, well, luck. Personally on the last levels I like staying close to the center. Sure, edges seems safer, but purple balls can quickly run along the walls and take you by surprise. Whereas on the center, there's more projectiles to avoid, but you kinda can see them coming.
I'm glad that you appreciated and, and were able to reach the end!