The cat ammo supply idea has potential, but is not well executed here. It adds a layer of frustration when you can't keep your fully upgraded cannons full, and makes the multishot and triple shot upgrades detrimental since they use up limited ammunition for red ball and blue ball. It would be better to add more levels to the cat upgrade.
The cat ammo feature is also buggy.
Balls missing is not satisfying. Add a path to upgrade it so that balls stop missing. Otherwise, there is literally no point.