Aw thanks!! We spent a lot of time just trying to get the looping to feel right -- we went from having the player click down every single time the loop broke, to having it be seamless and just allow the user to draw as much as they want without needing to lift up the mouse.
You're definitely not wrong about the upgrade screen, though! We noticed that as we playtested once during development -- we just had a tiny bit of sunk cost in the current design that we wanted to keep grinding out new features. Thanks for the feedback! :D