Thank you so much for the kind words and the feedback! It means a lot! We were in a 12 hour crunch when we made that tutorial, so there were some details missing, that weren't explained/were poorly explained.
The lever mechanic was poorly explained (it made sense to us devs, but it could be confusing to players). The idea was that you need stored power (generated from clicking the button) to be able to flip the lever. So if you can't flip it when the lights are off, you should try clicking the button to generate power :)
As for the core, the game gets harder over time (power decreases faster, and core gets more unstable). Also, clicking the button too much (getting more power than the max) will not only cut the electricity, but will give you a penalty, increasing the core unstability.
Anyways, thanks again for playing and for the amazing ranking praise, we really appreciate it! :D