Sorry to be a downer, but this really isn't good. The physics need some work, other commenters have mentioned "floatiness" and I'd have to agree. I can't decide if I think the game moves too slowly because I don't know how it would feel with better gravity. Also, one of the things that makes these kinds of games work is having the ability to see more screen. The skill in these games isn't in last-minute Hail Marys across the screen, it's in timing and angling your jumps to climb strategically up a scaffold that you can see a second or two ahead of time.

The lack of visual polish is obvious, and while the addition of a more dynamic sky would help I think the biggest issue is the hideous menu screens. Multiple typefaces is already an issue but the flat-color-plus-drop-shadow clashes terribly with the otherwise pixel art style. Also, the layout of the menu screens is really tough to look at. Also also, the color scheme of the menus doesn't match the color scheme of the game. Based on the overall visual presentation it's really obvious/unsurprising that most of the assets are taken from elsewhere.

I know I've had a whole lot of bad things to say and not many good ones, but I don't want to come off discouraging - this is still a hell of a lot more functional and playable than plenty of beginner games, and you've clearly got a lot of the basic skills needed to make some games. This is a solid starting point, even if it ain't there yet.

A beginner game, huh?

The game is rather floaty, try cranking up the world gravity and then scale the numbers as you see fit.
The aesthetics are beyond programmer art, but I too have this problem often, and need to be reminded by designers that stuff I make is ugly.
What would improve the game quite a lot would be a background image of some pixel art sky, just embed it as the camera's child and see.

Good job having the thing done, hoping to see you improve!

Remind me of many phone games, nice

I'm a unity developer and I can see that you used free assets, that's okay if you just want to sharpen your programming skills. Now, to tell you what is right and what's wrong with your game! Good:- Uhh.. Bad/could use improving:- Perhaps add a collider around that camera, the player can jump on hidden platforms. It could use some better fine-tuned physics. Perhaps remove the "jumper" part of the name as everyone know that platformers are based around jumping. I have wrote this review to help you improve your game, good luck!

Did some say custom assets and physics?