physics works wrong

[somber rose]

You probably should be setting velocity.x to your normal walking speed or similar while jumping, otherwise it'll get set to zero and stay zero the instant you hit a vertical surface.

(you'll need to set the horizontal speed every physics step if you want it to keep moving in a direction even if it hits something)

Oh, I misread the problem. I thought you wanted to be able to jump through the gap.

One problem with Godot's 2D physics is that it has a bit of a buffer zone around all your shapes, and that means that shape will sometimes hit each other when you think they shouldn't.

I think it's controlled by the safe_margin property.

But it might be difficult to completely eliminate it.

In my platformer, I gave the player a non-square collision shape and that helped with a lot of weird collision behaviour.

Maybe bevelling the top corners would help in your case.

You might not want a round-bottomed character in your case because you'll probably slip off corners.

Try making a custom polygon instead.