You’re welcome, Midhil, and thank you too! I’m glad for being able to help you somehow. ^w^
As for your question, you’ve managed to do a good work in the graphics and effects, specially within 3 days. I absolutely love how the main character has a bouncy animation for when it jumps. With all of that said, you should consider paying more attention to the graphics to come with something more polished.
Take the platforms as an example. They’re just a red rectangles, they look more like something meant for a prototype or for a debug run than something you would expect for a game. You should take in consideration where exactly the level takes place. Is it in outer space, or in an alien planet, or maybe in Earth?
Judging by the background, I guess it takes place in hills and mountains. In this case, instead of a red rectangle, it could have been, instead, grass and land, or even a more arid terrain.
GDevelop has a Platform Game example, you should consider looking at it and see the graphics. Even if they’re simple, they still manage to inform you about the world where it takes place, making it more believable instead of putting a number of random objects and assets to create a level.
Since you prefer to create vector-based graphics, you should also look for more inspiration from other works. You can always look for vector images and vector assets in Google Search or other search engines. Again, we’re looking for inspiration to create your own assets, if you decide to use something, be careful with the licenses and see them carefully to avoid getting a headache in the future.
As about the music… Sadly I was unable to hear it. I’m not sure if it was something with my browsers or my system, but I was only able to hear the sound effects. Please forgive me for this.