Cool idea, very easy to softlock though. The Summoning upgrade is super dangerous, if you buy too many ranks of it before getting any of the boss upgrades it becomes impossible to reach the boss. Every time you hit an enemy it deals damage, and there aren't enough survivability upgrades in the part of the tree you can reach without boss currency to survive hitting that many enemies. Seriously, if you max all pre-boss upgrades, you still can't get far enough to even see the boss. Could use more survivability upgrades placed at the start to negate this, gotta start a new savefile now. Like the idea of the game, though, stacking bouncing projectiles is satisfying.