Thanks a lot for playing the demo and for the feedback — really glad you enjoyed it!
I’m aware of the issue with repairing/upgrading and the yield signs. I’ve managed to reproduce the bug, but it’s quite tricky and inconsistent, so I’m still tracking down the exact cause.
Regarding the yield signs — they can currently only be changed while the simulation is paused. I realize that’s not very clear, so I’ll try to improve how that’s communicated in the UI.
Really appreciate you taking the time to report this!