I played through your game about 5 times. Here are some observations:
- I liked the retro design for the game. Kind of Mario-esque, but different enough.
- Liked the background music and the sounds. I played a couple of games in this jam that had no sound, and it instantly makes a game feel less full.
- Wasn't the biggest fan of the auto-walk, but I understand that's a design choice, and it didn't take really take away from the game play that much.
- The double jump felt a little buggy. Sometimes it wouldn't work.
- It was cool that you included a highscore board in the game, but that was a little buggy too. Some of the names didn't line up with the correct score.
I think this was pretty good for a first game. Keep developing and refining this game, or take what you learned and apply it to your next game, and you should have a pretty fun game!