Adding Keyboard Remapping Options - Later on

i would like to ask you guys how hard it is to implement a keyboard key remapping option
to a already “fleshed” out unreal game.

in this case i talk about street fighter v

i just want to know if there are some strugggles to implement such a feature later on when the product is already
in a somewhat complete state or not.

thx in advance.

Beyond creating a third party wrapper of some kind for the executable, it is impossible with out access to the source code or some inbuilt API that you can leverage to do so.

maybe i worded myself wrong or i understand your reply wrong.
the question was not if it would be hard for me to do so but for
capcom who created street fighter V or more to say hired people to do so.

the game is out since last year feb and that feature is still not implemented.
i just want to find out if they dont add it because there are technical issues or if they just dont care.

Ahh, gotcha.
In that case, no.
Provided the code shares still shares the basics of the engine, input wise, the hardest thing to do would be to create the UI.

ok, thx for the info!