Thanks for trying out the 3d levels. I've gotten feedback from others that the 3d mechanic is a bit hard to use/understand. I'll improve the tutorialization.
It's a good suggestion to add more early levels. I've removed some early levels to get people to the 3d levels faster. In my experience people don't play entries to full completion.
Regarding the symbol, it's meant to represent that you have to get two units of power there. I agree that it's a bit unclear. Maybe a battery icon would make it clearer.
Regarding the wires being broken: yeah it's a bug.
Thanks for playing. It's great to hear that you enjoyed the puzzles.