Thanks for the detailed feedback, really helpful!
Brave battery saver — good catch, I wasn't aware it's on by default on PC. The game uses delta-time clamping so gameplay stays correct, but the visual tick rate will stutter when the browser throttles background timers. I'll look into using the Page Visibility API to pause/resume more gracefully.
Tier timer counting fast — that's a real bug, thanks for flagging it. The timer is likely displaying in game-time units instead of real seconds. I'll track it down and fix the display.
Power/fuel display — you didn't miss a tutorial, it's just not explained well enough. I'll add a clearer label or hint near the power row so the fuel→generator→power chain is obvious before you experience it for the first time.
Fire progress bar — love this idea. A 5-level segmented indicator would make the fire urgency much more readable at a glance. Adding it to the list.
Once again. thanks again for playing and for taking the time to write this up — this kind of feedback is exactly what I need and I hope you will play and help with the sequel as well and help me make it better!