I have a few suggestions, and I think it may be because I've made games that looked and felt almost exactly like this when I first tried making games as a hobby. 

For the character, it feels a bit stiff and, as others have pointed out, would really benefit from some "coyote time". I'd also recommend adding a little bit of velocity or drag to the horizontal movement to make it feel a bit more organic. You want the response times to player input to FEEL instant, but they don't always have to be Exactly instant. Otherwise, things become pixel perfect, which a lot of my old games suffered from. It helps a lot when the player needs to make small movements.

Another thing I'd suggest is to put some decoration in the background, even if it's as simple as a couple layers of clouds. Having multiple layers can increase the perception of movement in the environment as it creates depth. It also helps the levels feel less flat. You only have a few platforms here and there so most of the screen is empty. 

I was initially impressed with the title screen and thought it looked good, but the rest of the game felt like it didn't match that artistic quality. When it comes to menus and UI, it's important to have responsive interfaces. When I hover over a button, it should respond to the player either visually or auditorily, or both preferably. For example, many games have a slight click or tick sound and change color or size just a bit when hovered over or clicked on. It really helps polish the game. 

I also would suggest changing the music in the level. It felt a bit too sharp and discordant for little guy climbing through the clouds. Using a lot of strings or synthetic pads might be a good way to create an atmosphere that reflects the visual tone of the game. 

I hope this gives you some helpful perspective, and I wish you luck as you continue your gamedev journey!

i like the game its just the jumping feels a bit werid for me but idk

I liked the game and i have some feedback :
- First the text in the UI and the guide to the player text was really small and hard to read, maybe u can make it easier to read if u scale it up

-The jumping from the platform to platform is a bit harsh, i think if u added a little more collider like what celeste did  like even if u missed it for bit u can still jump
overall nice game

very nice and cute games, i do have some feedbacks tho.

- from what I saw, you probably placed the shard counter text in the player in godot, and that's why its moving with the player. i think you could've just placed it where u wanted on screen and it will just stay there.

- as a platformer, this game is in dire need of "Cayote Time" (letting the player be able to jump a few frames after walking off a platform), it will make the game feel much better.

other than that, very nice game, i loved the visuals and the music and the player! good luck with your next games!