Can you explain gravity in 2D space?

...by definition that hypotetical would be a 3D space, not 2D.

You would not have centripetal force (which is what gravity is) on a 2D "flatland" world.

A 2D world would have width & depth...
lacking height would not have the axis for gravity to work on it.

Why not? Super Mario always comes back down when he jumps.

Think flat piece of stretchy 10 mile long rubber.
You traverse that rubber the full 10 miles.
While standing at the end someone stretches that rubber out to 20 miles.

You just traversed 20.miles with only expending the energy if traversing 10 miles.

That in a nutshell is gravity and wormhole technology.

You are welcome. Use it wisely and compassionately ease.

Doesn't any 3D object have a 2D surface?

We in somebody coposition notebook , with the graph sheets informal

Besides that Mario is a cartoon depiction it is a 3d "world" on a flat surface of the TV.

It has Height, Width and depth,
as you can Jump up/down, move right left, and there are objects behind the character. Hence it is not flat.

Same as a photograph or a good painting, seems 2D, but it is a flat representation of a 3D enviroment. Same with the game screen.

If you are serious about the subject, research "centripetal force"...that is what gravity is. An more interestingly, the distortion the centripetal force creates on the fabric of space, breaks open the Field's 4th dimension, time.

2D 'space' does not exist.