You should make the font more readable on your itch.io page. because you have the most important part of your game on the pageand not inside your game, players will need to read your page more often and the font is not accessible.

It's nice to have a stylized font, but you have a lot of content on it and it is best if it's easier to read.

Game ui

On the left you have what seems to be a control panel / keybinds. It's not clear why the collectible echo is there for and should be removed as it does not have anything to do with the controls.

Instead of having 'press these to open', use a mouse icon that has the right click down. 

instead of having 'to pull' just put pull. It is easier to describe actions if you have no way to show it graphically. Also this is something that should be on a separate window. Have a button that says controls and put it there.

In-game

It feels a bit empty without music. The jumping height is not very good. Would be good to have a tutorial to play, not necessarily to explain the controls, but moreso explaining what the echo mechanic is since it is the most important part of your gameplay.

I can see that this platformer relies on using the echoes to get further into the game, but it seems like it was designed intuitively and not with player experience in mind. You need to explain especially what you mean by input based. I think the second area needs the echo to have more time to get across.

The player is hidden on the game screen when it goes too far left. You should be adding a collision or boundary there. I think it takes too long to finish areas and not in a fun challenging way.  Overall, the game mechanic as a concept for echos is very interesting, but not utilized well in your game. Player experience can be increased by the changes above. I think the most useful feedback you can get is from new people playing this and sharing their opinion on your mechanic.