Well, I think the most important thing I learned from this jam is just how much I can get done when I really put my mind to it and I'm under a deadline. As far as game dev goes, I learned (or more like relearned) concepts with Unity's animator that I forgot about. The last two things on your list also resonated with me as well with the canvas and organizing code in a neat and efficient way. There were some things that I wanted to change but ended up couldn't do it quite so easily because I hadn't planned it out quite so well. Created some wonky workarounds to make things work, but if I continue with this project I definitely will be refactoring a good amount of code.
I think as far as art goes, this jam has really made me want to get serious about learning pixel art. I think I made the best use of the assets that I had, but I wish everything had a uniform art style. I would love to create nice art assets to go along with games that I make in the future.