You shouldn't let yourself use success and failure to immediately make judgement calls about yourself. Yes, you made some good decisions which led to the demo being popular. IIRC, it was one of the most polished games in itch at the time, with well-developed music and art style. You probably made some wrong decisions when making the full game. That just is. Game development has a lot of uncertainty. Even the best designers make bad games or good games which don't sell or don't meet their expectations.

I played the demo when it had come out (a year ago I think). I didn't make it far, because although the mechanic was novel, I found the controls really awkward and counter-intuitive. I also didn't like the tone of the game. It was too sad, dark, and lonely for me, and that really repelled me away. FWIW, I didn't like night in the woods either because of the same reason. Too little gameplay innovation, and too much dark story/tone.

I think you made a really complex game with a lot of polish, and you should keep going. Make some smaller games with minimal/no art to hone your game mechanics design skills even more (since you're already good at the other stuff).