It's me again.
On Safari game is running smoothly.
I really enjoy the idea that after progressing, the previous eras still have an impact on the game loop.
Thank you so much for letting me know! I'll be sure to update the game page to warn other macOS users so they know how to get it working.
Thank you for the kind words :) I am hoping to get the balance such that there's a need to revisit previous areas each time you upgrade, but right now it gets ridiculously bottlenecked on stone tools. If there's anything else you see that I should fix let me know!