Well done! Submiting a project in a game jam is to be celebrated and used to learn.
The basic movement was nice, but the jump felt a bit weird for this game. It was kinda slow and floating while the other elements of the game were faster paced. I think we as game developers (designers, programmers, etc) should determine what kind of experience we want the player to have and stick with mechanics (also count changing parameters of mechanincs) to enhance that experience.
I see on the game's page that you get more powerful when you die, but in game I think it lacked feedback on how the character was getting more powerful. While on the topic of the game's page, I recommend adding a few screenshots.
I know this project only has 1 level, but I think it isn't well introduced. Before the player realizes what it has to be done there are shots incoming from everywhere. Maybe create the respawn point in a hub room and you open rooms when defeating all enemies on previous rooms and follow the 4 step level design. On the first room you introduce one enemy with boxes in front of it so players will know what they are facing. On the second room remove the boxes to make it more challenging. On the third room a twist on the enemies behavior (maybe now there's one that is moving). Lastly on the fourth room the conclusion so that the player proves the mastery on the gameplay.
I hope this feedback can help you in any way. Don't feel discouraged and keep improving.