This is a very nice puzzle game. I stopped after a while since it seemed to go on forever (which impressed me btw so kudos), but I felt that it would be great to have like a menu or some sort of progression UI to tell the player where they are in the game.
So far, this looks like the best game that fits the theme of building connections. I'm also amazed that you made it using your own game engine. It's something that I was looking into doing so now you've officially inspired me.
The pixel art was nice to look at, but I felt a bit confused in the beginning when trying to connect the right colors to the lightbulbs. The colors of the dimmed (or disconnected) lightbulbs weren't completely intuitive with their energy color. (Ex: Dimmed Red Bulb was White, Dimmed Yellow Bulb was Red-ish)
Overall, stellar work!