Really good for your first game! Nice art and solid gameplay. Nice work!

Honestly I didn’t like it a bit. I can’t hear anything but my footsteps, which the reason I didn’t continue it

It's very successful for a first game. I'd recommend watching some videos that discuss quality of life mechanics for platformers (like coyote jump, jump buffer, etc.) I'd also appreciate some save points. It's frustrating to go back to the beginning because of one mistake. Personally, I would recommend when creating game jam games to make the game as simple as possible, because otherwise, due to frustration or lack of content, players who will try your game will leave it. But as I say very good job.