I think there is some potential here in terms of game play. A couple of items I would suggest:

1. Being able to see how much damage (raw and %) each ball and ability does over the course of a run would help with understanding which combos work best.
2. Poison seems to do what fire does but worse. It probably needs a bit of a buff to take it over fire or lightning. This could be in the form of more damage, applying vulnerability (take more damage from other sources), or leaving a puddle to infect others.
3. Either the display of the damage values or the actual calculations are wrong for snipe and momentum upgrades. I had unlocked them, but my normal white ball was still only doing 12 damage to enemies.