You have good taste making a 2D platformer! I like the visuals too. I have a feeling you used an asset pack, and if you did, make sure to credit the artist for legal reasons or at least as a nice gesture.
I have some experience making platforms. You did a good job with the level design! It was entertaining and varied. There's definitely places that were a bit too difficult (for example, the jump over the second bee in the first level is challenging to players who haven't had time to learn the arc of the jump yet), but under the constraints of a game jam it can be tough to playtest and find those, so I completely understand.
I'd recommend watching some people play the game to see how you can improve. You'll learn a lot about game design if you're observant. I also recommend watching some game design videos on platformers. Platformer controls are all about the little details, so you need to make sure you learn all the little tricks. Here's some you could look up to get you started: jump buffer, coyote jump, camera drag, variable jump height.
I enjoyed playing it and I hope you do more work on platformers in the future because they can be a lot of fun!