Nice game! Here's a few things I noticed:
- The Merge feature is not obvious and the later balls are more cost efficient initially. I completed a few Prestige using no more than 3 of any ball before I discovered Merging.
- There doesn't seem to be a benefit to pushing for a high level. You seem to get more Diamond per second if you prestige as soon as the game slows down. There is no goal to grind towards.
Idea: a loadout system.
- When you reach certain levels for the first time you unlock a new Ball type.
- When you Prestige, you can choose 5 balls you have access to for your next run.