Lovely game. I really enjoyed how much was in this game, usually game jam games are a few minutes long or less but there was quite a bit of content and great detail. I appreciated the backgrounds though I did notice they got less intricate the more you got in the game (time constraints eh). I also loved the world map, even if it was a little bit bigger than it needed to be.
The minecart double jump was really fun to use and took a little bit to get used to, it wasn't immediately obvious you can use it mid-air. I also felt it wasn't obvious where you should be going a couple of times, like having to make big jumps to the left in the level you got the minecart. I also didn't know what to do after gaining the powerup in the mines, it took me some time to figure out you can wall run.
Overall, super solid game! Looking forward to a "finished version" if you'll ever work on it!