It's seems like that it's one of the first games you ever made. Congratulations for that! It's not the best game, but here a few tips and ideas to make it better:

- You used background colors that are very hard to the eyes. Instead of red and green you could try to use something lighter. Maybe a softer shade of red.
- You can't get killed by the enemy. He is chasing you around but nothing happens if he catches you. The game should end if he catches you. Or better: have an health bar and health items around your level.
- You can jump multiple times without stopping. Maybe you could check in your code if you can disable the jump if the player is in air or something like that. I'm not a programmer but google the issue, I think you're not the first one to experience this problem.
- Your level is pretty enclosed. You could try to add platforms next time. The only way the player can go is right and left. Vertical space is sometimes also very important.
- Add a goal like collecting something special. Just killing the enemy and ending the game isn't fun.
- You have no music or sounds playing. You should first focus on your game and as a beginner you can use royality free sounds and music to fill your game. As you will become better you will want to work with a sound designer, as it is an important part of a game that gets you immersed.

Hope to see your progress in the next jam! /alex