I was immediately reminded of Johnny Upgrade when I started playing and then realised why once I read your comment about being inspired by that game. Even if simple, the amount of nostalgia and joy/whimsy it has by allowing you to become pretty much the greatest ball in existence makes it great.
P.S. Just as a side note, the current value of the upgradeable variables show up as 0 and only display their current values once you upgrade them again on the upgrade screen. If you ever decide to update the game, you can fix it by copying the lines of code that make the labels show the variable's values into the function that makes the upgrade screen appear.