Thanks for jumping in, PhoenixInDaBox!
Exactly. If you upgrade "SCORE UP", you'll keep earning score even while idle, and you can spend it on more upgrades. I've added this to the description too. :3
Thanks for the feedback! I just pushed an update based on it:
Thanks for pointing out the monochromacy issue. I hadn't thought about it. If anything still looks hard to tell apart, please let me know!