Addictive fun little idler. Great visual feedback + choice for upgrades!
My one recommendation (and what's typical of some idlers) is to add an interactive component. For most idlers, that's clicking on something. IMO these games work best when the player has just enough agency to make them feel like they're getting ahead by doing something manually (and missing out on progress when they're not).
That's just my 2 cents though. Great work!