Came here from the game jam since I wanted to check out your work. This is a really cool project and looks so different with the 2.5D. I know you said this is your first platformer, but I think it's really good.
The only thing that feels a little funky is the movement in the air after jumping. Once I jump then move to the left or right with a tap, the player moves very quickly in that direction without slowing down. Although it's a little unintuitive and unrealistic, most platformers don't keep momentum in the air since it gives the player much more control. I'd suggest adding some "air friction" or the player instantly stopping in the x direction after the button is released.